$400 soft bubble multi-way turn decision

If my math is right you still had about 78k back when it was checked to you on the turn?

It's kind of an awkward stack size. If you were a little shorter I would just jam.

At this stack size I would lean towards a check back, planning to call a lot of non-completing rivers if one of the players bets into you.

The river is where live reads come into play. Rivers I would strongly consider folding include non-spade 6,7,8,9 and J. If BB bets big on a non-spade 2 I might also consider folding. But again it's based on live reads. BB really shouldn't be over calling with many 2x or 7x but I see it happen all the time from certain recs. So you'll have to be comfortable making some reads on the river.

The nice thing about checking back is that I would expect rec players might try to bluff a spade river when they're weak, so you could get some additional value when you river your flush.

The alternative line would be to bet-call off turn with top pair plus a flush draw. If you bet and get called you could check back a lot on rivers when you don't improve. I like this line better against regs honestly, who will balance by checking some strong hands on the river.

The villains you described are the type that I expect to donk-jam river a lot, both for value and as a bluff. So it makes the bet turn, check back river line less appealing.

Anyway I think there are pros and cons to both a bet and a check, but I lean towards checking turn and calling a lot on rivers (obviously likely jamming over a bet if you river a flush).

Problem is there are so many bad river cards. Aside from those already mentioned by you: What about Q K A? Would it surprise us if old lady went open bet check with hands like AJ or KQ, perhaps suited in clubs or Diamonds? Or BB going call call check with QJ or AQo? I don't love betting, but I think it gives hero a much better chance of winning this pot.

Ya I'd just bet 20-ish K and check back any river I don't improve on. Don't expect to get check jammed on much here and don't want someone betting huge on 3x river.

Result: I ended up jamming, BB folded quickly, UTG tank folded what I assume was an overpair

I don't hate it for the reasons posted here:

The problem is there are a limited amount of hands that we're ahead of that can call. Like even TJ could conceivably fold to a jam. T9 and 89 would likely call with the pair plus open-ender I guess.

The jam can't be too bad though as even if we run into a straight or two pair we've still got equity with the flush draw.

I guess jamming could be the best play? It has the strengths of getting a lot of hands with significant equity against our hand to fold, and we always realize our equity/ never get bluffed out on the river. Tough spot.