I like sopuli.xyz, mander.xyz is pretty cool, in general I recommend browsing your federated/all feed and checking out the new instance names you see and notice the instance names of the communities and users you seem to vibe with or that talk about things you are interested in.

Make accounts in a couple different places, to a reasonable degree you aren't wasting anyones time if you want to try out a new instance but don't end up liking it!

If you want you can use the same name as your account name on lemmy world so that it is easy to remember and for other people to know you are the same user. If that is what you want of course, that is just a suggestion if it feels overwhelming.