permanently banned for "report abuse" because I kept reporting people calling for genocide in Gaza

I am 90% sure that the people you are talking about were doing no such thing, but were expressing some view which in your mind might as well be affirmatively calling for the deaths of millions, even if, that's not at all what they said. If you're planning to consume mod resources in a futile effort that they punish people who express a view which you're hostile to, until the mods get sick enough of it to permaban you, in all honesty I think it might be better to chalk that up as a lesson learned. People are allowed to talk, even if you don't like it.

Maybe I am wrong and they were for-real "death to Arabs" people who should have been banned and the mods just couldn't see it, but I think the mods are probably pretty anti against explicit violence. I base what I'm saying only on what I've observed on Lemmy in terms of people treating perfectly legitimate views as "pro genocide" and getting real aggressive about it, when the views being expressed are worlds apart from pro genocide, and the community as a whole is pretty unanimously anti genocide.

Be that all as it may:

I installed the app on my device and it tried to use my old credentials, which I attributed to the OS remembering it. I then made the mistake of commenting in r/news

Detecting ban evasion is a rare category which the admins of even networks that generally don't give a shit about bad behavior tend to put some effort into. If you're going to do it, I think you can assume that any browser / any device / any network which you previously accessed Reddit from is more or less "cursed" as far as, they're going to pick up that the fingerprint of the device is the same and maybe ban you again.

I'm not sure what you could honestly do, barring having a virtual environment on your phone for just the Reddit app. I have no idea where the line is in terms of what can show up as a duplicate of the banned device but I know it's pretty comprehensive. IDK. If you always did it from the app from your phone, you could maybe switch to browser-only on your phone and gamble that they won't be able to fingerprint it enough to detect that it's the same device.

Of course, that said, there's no harm in uninstalling and reinstalling the app and trying it out on a new user. But I would be pretty surprised if that worked on the same device no matter what you did; I feel like the device fingerprint based on using the same app is sufficient for them to ban the new account.