Thank you all for the feedback and analysis!
Here’s a little bit more about my thinking during the hand, responding to some of the questions in this thread.
That preflop raise size is just something I have been experimenting with. Typically I would just always hit the “pot” button for preflop raises, which gives you 3.5BB + 1BB per limper. I have been finding that this size isn’t big enough to isolate though - I’ll frequently get 4-5 callers. Generally at 20/40 the magic number seems to be at least 300k to get it down to 1-2 callers.
In general in this hand I was less worried about V1 and more worried about dayman behind me. When dayman flats I was thinking he had some sort of small-medium pocket pair or maybe another suited connector-type speculative hand that he decided not to 3bet.
When the flop came 765ss, I was thinking that in general this is hitting both other players more than it hits my general range. I certainly have all the big overpairs that they don’t, but we also all have all the sets and nut straights. They have a lower density of random overcards than I do - especially dayman who is likely to have 3bet a bunch of things like big Ax hands.
When V1 donk bet, I felt somewhat confused. My general read on this action with a straightforward player is that they are quite strong, and their range will include straights, sets, 2 pairs, overpairs and some A7/K7 (though I block A7). I think there are also some pair+OESD hands possible. Overall I figured I am ahead of a lot of this range but I want to let the weaker stuff stay in so calling is better than jamming right now. If I jam, all the weaker stuff folds and the stronger stuff calls, which is a bad situation. Plus I have another player behind with a potentially weird range that includes a lot of stuff that smashed this flop too.
When dayman called behind, I felt very confused. At the time I was thinking that this only really made sense with something very strong (i.e. a straight or maybe a set) that decided to slowplay. Looking at it now, I can see that a lot of draws have great odds to call and take a turn with so any kind of flush draw or OESD makes a ton of sense. Sets and even straights are more likely to just get jammed right away on the flop.
When V1 lead-jammed, I was left trying to figure out whether I could be ahead of both of the other players still in the pot. At the time my gut feeling was that I was in trouble between the two of them.
In general, I feel less confident in a large multi-way pot than heads up. Heads up vs V1’s donk here I just go call flop, call turn (if bet into) or jam myself if V1 checks. Against two or more players though I don’t have a great instinct for how players’ ranges are stacking up - particularly when there is an unconventional action like the large donk bet.
I will definitely check out Flop Falcon - sounds like it can be helpful in this kind of situation.
I made the nitty fold on the turn. Dayman calls. V1 shows Kh6h for middle pair. Dayman shows 8s8x for an overpair + OESD. I start banging my head on the keyboard. River is the 7d so dayman takes it.