To add onto the conversation in the comments: Simba in The Lion Guard is... different. Most of The Lion King characters are; the only two who seem similar are Rafiki and Mufasa. Honestly, even Scar seems different.
(I think he's more snarky and short-tempered, but that might just be me.)
But Simba? He’s... different. He was different in The Lion King II: Simba's Pride too, actually. In that one, he was more paranoid and anxious, especially around Kiara. In The Lion Guard, he’s not as paranoid, but he still seems anxious and snappy. With Kion, he seems more short-tempered, such as in the “movie,” where he got mad at Kion for the Guard he found.
Yes, it wasn’t traditional—only one lion, a cheetah, an egret, a hippo, and a honey badger—but it was still his Guard. And as Rafiki later states, when Anga joined: Kion is not one for traditions.
My brother said that Simba might be scared that he isn’t living up to Mufasa’s standards, but then again... hate to drop a bomb but it seems like Mufasa died before he could teach Simba much about being a king. And, also, Simba was more or less forced back into being king due to having to overthrow Scar after he overthrew him. He told Nala he didn’t want to be king, and if he didn’t have to, I honestly think he wouldn’t have.
Another thing I don’t like is good behavior in several scenes with him. Two good examples are how he acted when Kion got him to help Bunga with the Twelve Ways Of Christmas performance for Timon and Pumbaa, and the other is when he got mad at Kion for not telling him the message, and then mad Bunga for snowballing him, but he just laughed when it was because of King Sokwe.
AND ANOTHER THING. I hate his behavior in Bunga and the King; yes, I know he doesn’t like Bunga, but he was unnecessarily rude. It felt so uncharacteristic for him, especially because I’m pretty sure Timon was like that too. I did like how they sang Hakuna Matata together, and I thought it was cool that they are technically brothers because Timon and Pumbaa adopted them both, but I dunno... Simba was too pissy. Maybe he was just sore from the fall, or maybe it reminded him of Mufasa’s death.
Speaking of Mufasa, real quick: I feel like he likes Kion more... but that might just be me. Kion definitely respects Mufasa—which is great!—but I still feel like he was closer to Mufasa than he was Simba... meh, maybe I just am overthinking it.
Anyway, I will shut up now. God, how did I rant this long? Sorry LOL
Holy shit I was NOT expecting an essay on TLG Simba’s character but I absolutely agree with pretty much everything you said. Simba’s characterization is definitely one of the show’s flaws cuz he was never that short-tempered in either movie. Like you said, paranoid/anxious, sure. But he was never as mad at Kiara then he was with Kion
That being said, I didn’t have too much of a problem with Simba at the end of The Lost Gorillas episode. I think it was mainly for a joke and he was never really mad in the first place
You make a really good point on Mufasa’s death contributing to Simba’s attitude! When you think about it, Mufasa didn’t get to teach him how to be king so of course he’d seem inexperienced with ruling a kingdom. I hc Sarabi somewhat taught him how to act like a king :)
Also I’m pretty sure Mufasa interacting with Kion more than Simba is a running joke in the fandom. Classic grandparent spoiling their grandchildren lmao