I think the best ActivityPub software for mainstream adoption right now is Pleroma with @soapbox. One could say it lacks carachter, which is true, but it's less buggy than Mastodon (as far as I can see) and it has a really beautiful UI, which is necessary for "normies". It could get some hints from Misskey - like the way it handles comments, which is more Reddit-like and way easier to read imo - but it's already miles ahead of others.