A company should have the right to enforce the terms for its own platform.

No, I think what they mean is that for instance, Apple Music is on Android, but Apple takes payments through its own platform, not through Google Play, therefore denying Google their 30% cut on apple music payments. Many smaller companies are not able to negotiate the same thing.

Massive off-topic aside: Would you mind stop referring to me as he, and more generally don't assume someones gender identity. Sorry about it, just shitting me off a bit lately.

Huge apologies, I normally just use "they" when I don't know the gender, honestly no idea why I didn't do that here. Sorry about that.

Oh I didn’t know. I guess supporting Epic means that kind of behavior will just continue if they win...

That's very unlikely, because the court can't force Apple to provide a special deal to Epic. Whatever decision they arrive at, it must be generally applicable.

Not if they're anti-competitive, like selectively using private APIs or forcing developers to use unrelated services (i.e. Apple payment processors).