reposting this incredible hobie analysis by @lizzytheowl577 i stumbled across in a youtube comment section
Spoilers ahead
Ok so Hobie was all set to betray Miguel the moment he realized that Miles might be in trouble. The first thing to tell us this is that Hobie actively congratulates Miles when he stopped the cannon event from happening. Presumably every Spider-person who the event isn't for gets an alert when one is about to happen to keep them from interfering, this includes Hobie. He knows Miles just broke the rules in a major way and he's estatic about it. If I remember right, he's the only person who actually congratulates him on the rescue (Other than Pavitr of course).
Next, when Miguel orders all of them to come to the Spider-Lobby (I don't think it had an official name and if it did I forgot it) Hobie puts his arm around Miles then says "I don't follow orders and neither does he". I initially read this as Hobie trying to keep Miles safe from Miguel, in a "We'll run right now if we have to kind of way" but the more I think about it, I don't think this is the case. I think Hobie believed that Miles knew he was breaking a cannon event and that's why he tacked on "and neither does he" at the end.
Once Hobie realizes that Miles is ecstatic to go to the Spider-Lobby, he starts to second guess himself. He asks Gwen how much Miles knows, discovers he knows basically nothing and on the spot switches to talking Miles out of joining. Telling him to make his own watch and that he wouldn't like being in this group.
When Miles asks why Hobie is even there, he's says he's there to look out for his drummer. What he doesn't say is that he's doing that by trying to help Miles. Through this whole conversation, he is stealing bits and pieces of equipment from the lab, and it's implied he uses those pieces later on to make a new watch for Gwen to use. From at least that point, probably earlier, he knows that Miles isn't going to sit quietly while his dad dies, and Gwen is eventually going to want to help him. Which is why he delivers the watch to Gwen instead of trying to go straight to Miles.
Later on, when Miles is getting angry about all the other Spider-People telling him to let his dad die, Hobie eggs him on. This is not just something he does impulsively. He realized early on when Miles talked about his parents that all he needed was a few nudges to go against Miguel's system. When Miles started showing signs of discontent, he decided to pick that moment to egg him on because that was the most effective time to. Then, Miles gets trapped in the energy prison.
Hobie helps him get out of it, but the way this is done is genius. He holds up his hands and mouths "palms". To everyone else this would look like he was trying to just calm Miles down. If they just see his hands, it looks like a "calm down" gesture, if they read his lips, "calm" and "palm" are pronounced similarly enough that seeing him mouth one word, they'd assume in that instance he's saying "calm" as in "calm down". This in turn does two things: It gives Miles the element of surprise, and it doesn't make it look like Hobie helped. Those two things give both of them time, Miles get a few stunned seconds of a head start, and nobody chases or tracks down Hobie meaning he has time to make the new watches. He even throws away his current watch because he knows it can be tracked and Miguel might go after him after realizing he didn't help try to catch Miles.
Basically Hobie is an incredibly intelligent character and they were able to demonstrate this really well in the short amount of time he actually got on screen.