I installed some community made themes (like darkspace) just to play around and give users some options, but yeeeah... none of them are very good. Thankfully the admin team knows a bit of CSS from their redditing days so a theme improvement is definitely on the to do list.
If anyone wants to have a go at making one, be my guest, I'd be happy to add it to the options.
We're aware of the pact and will cross that bridge when (or if) it ever really happens. We're certainly no fans of Meta (or Reddit,or Twitter). So far it seems more likely to affect Mastodon than Lemmy/Kbin.