Users are empowered to set what they want their default homepage view to be (“Subscribed” , “All”, or “Local”). I am unsure what the default is, but mine is set to “Subscribed” which I think it makes the most sense for most users.
Unless you are on a heavily moderated/defederated server (such as beehaw) whose moderation policies, politics, etc. you are aligned with it is very likely that “All” is going to contain something that someone doesn’t like. I am personally not in favor of over-policing what users do outside the confines of their home instance, it’s a fine line that I haven’t had to define too clearly yet so perhaps my thoughts here will change.
If you don’t like what’s in “Local”, then to me that is a sign that the instance isn’t for you. Local is a reflection of the sort of content that users on that instance want to see more of. The admin allowing such content is not necessarily an endorsement (unless they were the one to actually post it), but is tacit acceptance of that content and the community that content exists in.
I think some way to make a “Curated” feed of posts only from certain approved communities would be a welcome feature and present a useful middle ground allowing for a moderatable discovery experience, like the default subscriptions provided on that other site.
I would still go with one that isn’t one of the biggest. My general advice is to find one that fits the vibe you’re going for, communities you’re interested in (e.g. some are focused on art or cybersecurity, etc), or is somehow tied to your locality. It shouldn’t matter that much, though some servers will be a little more (or less) strict with things like federation, content warnings, alt text, etc. Usually the server will have some info telling you some of this, and their admin should be linked and likely has a post or two pinned to their profile explaining some of this as well.
I am partial to kind.social, though have opted to run my own instead of joining up anywhere.