Unfortunately it’s hard to replace local groups for me. It’s mostly crap but there is very useful updates there as well and I live in a small enough community there’s no alternative. I’ve used them to get rides, forest fire info, community event info etc.
I used to use marketplace as well but they’ve completely ruined it with shipped products and ads and stuff from too far away. They’d rather show me pages upon pages of shit I’ll never buy because it’s shipped or three hours away than show me just the five results for “dresser” within 20 miles of me. So now i only interact with marketplace through buy/sell groups. God I miss Craigslist.