I got a few new people on my instance that specifically said they wanted a smaller instance while Lemmy.world had issues.
I think there are like 1100+ instances now. No reason to hang out on the largest one unless you absolutely have to.
Once you have two or more accounts, it's just a click in the mobile client (Jerboa, Liftoff etc) to switch profiles. Takes a second.
You will have to set up your subscriptions to communities again though on a new account. That can be annoying but kind of worth it.