I also can vouch for sh.itjust.works. They have a fair defederation policy and has only gone down a couple times in the two years I’ve been using it. When it has the admin has been quick to address it and provides updates via a matrix chat.

The one downside is that some more niche domains have degenerated defederated (thanks autocorrect) from us due to the open enrolment we have (beehaw comes directly to mind). I recall someone linking a website that tracked what servers are federated with each other but I can’t find it now unfortunately.