Check near the bottom of https://join-lemmy.org/

There you can see the different options to support Lemmy.

In special I’m hoping for specialised instances about some subjects that I enjoy. I like the Lemmy instance but stuff like anime and conlanging “feels” off-topic here.

Do you mean for subscribing to the communities of these new instances, or would you completely switch to that instance (create a new account there)?

I’ve noticed some lags/asyncronity with non-home instance content. I guess it would make sense to be home wherever is the most and best fitting communities. But that would also mean leaving behind the stuff of the current account.