The most annoying thing about Miraculous writing and Thomas Astruc is that they make seasons that are saturated with filler episodes, complain about not having time to explore things and then tell you on Twitter or Bluesky vital information that should have been told in the episodes (and that a casual watcher or someone who doesn't want to enter the pits of hell that is Twitter such as me, could even not run into.)
The first 3 seasons don't really have this problem, because the only arc that was going on was ChloƩ's redemption arc and it went pretty smoothly apart from the finale where she gets replaced by whatever that thing is. And Fu's backstory was revealed too, and it was even done nicely, they first teasered it in S1, then in Sandboy we learn that one of his mistakes led to the temple being destroyed, and at last in Feast we get the full story (even if I think that he should have died in the S3 finale, but that's a writing choice I can get behind). The only bad thing about those seasons was Lila, we still don't know anything about her, what she wants, what her relationship is with Tomoe, why the fuck characters lose any kind of characterization around her and believe the worst lies I've ever heard of, but that could have been fixed giving her more screen time. Even the new miraculers were a good addition, their powers (except for King Monkey) were balanced, and they were given reasons to have miraculous: either to save themselves (Ryuko, Viperion, King Monkey) or somebody they care about (Rena Rouge, Carapace, Pegasus) with Chloe being an outlier and having found the Bee miraculous by chance (and getting to keep it after helping with Malediktor).
There are 19 miraculous, with Ladybug, Black Cat, Fox, Turtle, Dragon, Snake, Butterfly, Peacock, Horse, Monkey and Bunny not being handed out in this season. That makes 11 holders already introduced (or more precisely not to introduce this season) and 8 more to go (and to introduce in s4 because in s5 they can't give them the miraculous since Monarch has them)
9 episodes I can remember had any relevancy towards the plot (I didn't count Dearest Family because Hawkmoth could have used any other episode to break the magical charms). There are 26-9=17 episodes to actually flesh out these other 8 heroes. Let's make it 10 because they had to introduce Z*Ć© and giving her a miraculous in the same episode she debuts is indeed a bad idea. Instead, we had
Sole Crusher (introducing Z*Ć©)
Crocoduel (Purple Tigress)
Penalteam (Caprikid, Rooster Bold, Minotaurox, Miss Hound)
... Why are there 6 out of the 10 episodes they needed? Oh, because they gave 4 FUCKING HEROES THE SAME EPISODE TO DEBUT IN? AND THEY AREN'T EVEN INVOLVED PERSONALLY IN THE SITUATION APART FROM MISS HOUND? good, alright, then I hope these 11 episodes are at least important to some degree. Let's see.
Psychomedian (shit episode, useless, introduces an annoying character that should be important since he knows Gabriel since he was Gabriel Grassette but we never see him again. The episode is unfunny and they give the whole fight to Ladybug despite her being affected by the villain. Filler)
Furious Fu (introduces another useless character. Wether Su Han is in the story or not, it changes nothing because he is in so little episodes, that we have seen him for a total of 3 iirc. He brings up a fair point of Ladybug breaking the rules of the Guardians but he doesn't give us any lore about them)
Optigami (actually enjoyable, shows some good thinking from Hawkmoth and (mainly) Nathalie, but sidelines Chat Noir again. Which should be a theme of this season but they never actually resolve it.)
Sentibubbler (also enjoyable, if Rena hiding wasn't completely useless it would also be important for the plot, but she gets discovered in 3 episodes and she doesn't really play a big part. Wether she stays hidden or not, nothing changes from the actual plot)
Glaciator 2 (Marichat episode? What even happens in this one? Gonna rewatch it real quick...
... Literally nothing changes, nothing happens. I get why I forgot this episode, it's pure fan service with no consequences on the plot. The buttercup dialogue lasts for a third of the episode)
Hack-San (useless, Scarabella is ugly as fuck, what the hell is that yo-yo placement? Small Marcaniel moment but if I didn't care about them I wouldn't care about the episode)
Rocketear (I started to hate Nino. Pointless jealousy plot point, nothing changes, Alya already tells Nino she is still Rena, making Sentibubbler basically useless)
Wishmaker (they didn't know what to do with Luka since he's not a love interest anymore so they set him up to be put away in Brazil so they don't have to worry about him. If he wasn't in Brazil now, it wouldn't change much. And they could have just used the excuse of Jagged traveling the world with his son to make him go away, make it reversible if they ever came up with something and give him something to do while he is away)
Simpleman (iirc the favorite episode of TA. Do I even need to say anything about this one? So boring and useless that when I rewatch the series I don't even rewatch it. Nothing happens at all, it's unfunny, the kids are annoying, Roland is a useless character, and it's so so so so so BORING)
Qilin (bad analogy for police brutality. Bad animation. Bad plot. Nothing happens in the plot. Cool to see Sabine akumatized and they even got the mythology right for this Chinese character. Too bad the Qilin doesn't have those powers as far as I know, which my knowledge is pretty limited on the matter so help me with this one. Still a bad episode)
Dearest Family (kinda fucks up the timeline, Gabriel breaks the Magical Charms but he could have done that any other episode. Yet another episode where nothing changes)
Ephemeral (worse Chat Blanc (not that Chat Blanc was that great to begin with), one of those episodes where everything happens but it gets erased one way or another. They already did that with Oblivio and Chat Blanc so why do it again? Pure fan service)
Kuro Neko (chat gets offended for not being called like the other heroes I guess? Anyways, you guessed it, nothing really changes. This should resolve the arc of Adrien feeling excluded from the team by... Making Cat Walker too attractive for Ladybug to focus? And so she realized Chat Noir is irreplaceable? Yeah, sure. Their dynamic shatters just for this episode and they go back to normal at the end, just like in Glaciator 2)
Out of these 11, 2 were somewhat good imo, but they brought nothing important to the plot. Su Han could have been a great character but we see him 3 times. Luka learning the identities is underused. Shadow Moth breaking the magical charms makes Mr Pigeon 72 useless, and they didn't even wait a season to break them, they lasted 17~ episodes in production order and who knows how many in release order.
So the writers have no problems wasting almost half a season with unimportant shit and then they cry about not having enough time for the plot. They could have done a lot for the Agreste arc in this season. They could have at least given an episode each for every new miraculer. But they chose to put Simpleman instead. And then they never explain anything in the series because they thought it was so obvious. It happened off-camera. I fucked your mom off-camera, what about it?
This is probably my worst paced post yet. Not sorry about that.