If that matters to you, you pick an instance that rarely blocks, and then you can talk to both of them seamlessly.

Occasionally some people are affected because they've picked a major-ish but somewhat block-happy instance, in which case they can either move their account (the experience for a move on Mastodon isn't great but it does work) or create a second one if it really matters to them.

Usually people will find out pretty early on if they're on an instance whose policies they agree with or not, so even if the account migration is jankier than it should be, it's rarely a major problem (in that instance - if instances shut down it's more problematic)