I think the issue is that your are expecting a perfectly seamless, Reddit-like experience, with all the admin work done for you but also always done to your satisfaction. That isn’t what the Fediverse is about. It’s more of a DIY ethic than a “The admins suck but this is all we have” like on Reddit.

I’m also not sure what you’d need to “migrate” to a new instance other than yourself. Karma isn’t super relevant here.

My main account is on Beehaw, which has very rightfully defederated with some other instances. When I log in using accounts on other instances, I don’t see a massive amount of missed content. In fact I’ve seen so little of interest that I’ve stopped looking, it’s not worth my time.

You can always set up your own instance if you are disturbed by the actions of admins on instances that you have joined.

Alternatively, if the instance you are on changes direction, you can easily find a new one. It literally took me about half an hour after I learned about the Fediverse to get myself set up on several instances, then later on I decided which I preferred. But I didn’t delete the other accounts- they’re still there in case I want them someday.