Arts and culture is a very broad topic area. It covers (among other things):
- performing arts (eg plays, musicals, film, TV, radio)
- visual arts (eg painting, drawing, sculpture, crafts)
- literature (eg books, poetry, the various literary genres)
- design (eg fashion, typography, architecture)
Mastodon has several instances focussed on different aspects of arts & culture, eg:
Different lemmy and kbin instances have various arts & culture communities (some are reasonably active, some aren’t). You can use community/magazine search tools to find ones to your liking.
Eg to search for theatre related communities you could use:
- https://lemmyverse.net/communities?query=theatre
- https://kbin.social/magazines?query=theatre&fields=names_descriptions&federation=all&adult=hide
- https://browse.feddit.de/
Note that due to the way the fediverse works, these search aggregators aren’t necessarily comprehensive. So it’s worth spreading your search over several tools.
As I understand it, you don’t sign up to a mastodon instance with kbin. Rather, kbin has the ability to act as a way of following fediverse users and hashtags in the same way as mastodon does.
In other words, if mastodon is the fediverse’s version of twitter, and lemmy is the fediverse’s version of reddit, then kbin is a combination of the two.
However, while kbin’s lemmy/reddit features are maturing nicely, the mastodon/twitter functions are still pretty embryonic. (Bear in mind that kbin is a young project that for most of its life had only a single developer.)
For example:
What I would recommend for now is to create a mastodon account on a mastodon instance of your choice, and treat the two ecoystems as largely independent, until kbin’s feature set matures.