bbPress.org

that is a generic warning that bbpress throws up for all software that is not being maintained.

tweaks continues to work fine.

You could change it, but due to WordPress becoming obsessed with blocks, how to get it to work otherwise depends on may factors.

you could try this

Lightweight Sidebar Manager

I’ve not used it

bbpress has custom post types of ‘topic’, ‘reply’ and ‘forum’ – no idea if it will work

If it doesn’t – come back