Not sure, if you were thinking about folding or raising pre. You absolutely cannot fold hand this strong and it doesnt really matter, if SB calls or not. You are equity favorite and get discounted odds, its a must defend.
Don`t like raising either, it would suck so much to get 4-bet (probably have to fold) and hand plays very well in srp 3-way.

BU range is very flush-heavy for sure on turn. You block middle set and top 2, so its very hard for him to have any kind of made hand on the flop. You still beat A34-type str8-draws, but most of those probably have fd to go with aswell to raise flop. I dont think he is folding any flush to your bet, so I dont see any reason to shove. Prefer checking and folding to a push, youll sometimes get a free card too, if he is timid enough to check a small flush.

Call pre, as folding and 3bet are bad options.

You said that he has fd for sure, and still decide to bet. You have around 20% against the flush so shoving is -EV and for sure the worst option.

I would check and see how much the opponent bets. If he bets, I think he has the flush and you can see if your equity is enough to justify the call (if he bets). People like to slowplay flushes, so he might check his flush and give you that free river.

I bet near pot or pot OTF

Interesting that you block the 5 for 2nd set, so It hink checking turn is mandatory. Call a shove dependign on how ofnte you think he will shove a low wrap here or not.