Have some history/notes with both players:

BB is very very aggro pre, loves 3betting wide but tightens up post flop. Will make questionable loose calls on flops.

SB is more important for this particular hand, here are some hands of note:

-He straddled for $4 once, potted to $24 with 4556ss after some calls and snap got it for $150 after someone limp/repotted AAxx

-Called $4 pre w/ QQ72ss OTB, called $20 pot bet on KQJ FD with no FD. Called 1/2 pot $30 on a blank 4 turn, then full potted $100 on blank 5 river after being checked to and got snapped by 9Txx

-Called $24 on river board was 66KQ6, player he called had AK and it was good lol

OK so here's the hand (only 5 handed at the time):

UTG limp $2, CO limp $2,

Hero BTN ($600) raises to $10 with A Q T 6

SB ($600) calls $10, BB ($800) 3! to $32, UTG & CO fold, Hero calls, SB calls

Flop ($100): A K T

SB checks, BB cbets $46, Hero flats, SB raises to $112, BB calls, Hero calls.

My thought on the flop is I am very likely to be behind right now, but could hit gin/freeroll cards if a J J hits, could be good if an Ace or Ten hits, unsure. But, we are all very deep and as I'm in position I can see how the act on different turn cards etc...

Turn ($466): A K T T

SB nearly SNAP full pots $466 essentially shoving allin, BB insta folds...Hero??

My thoughts on hands SB could do this with on the flop that I now beat on the turn:

KQJT, QJTx...and that's about it

I obviously lose to AAxx & KKxx, however I would expect him to 3bet AAxx pre vs. my button raise. Pretty worried about KKxx here, but at the same time wondering why he would full pot the turn instead of go for value with AAxx or KKxx or even check to trap a hand like mine or get river value from straights, etc...

With the way you described V I could for sure see him having a hand like KJT8ss or Broadway and he is potting out of frustration/blind desperation that he may still have the best hand (I have seen it happen sooo often lol). If V had KKxx I could see him three-betting from the SB wanting to avoid a multi-way OOP flop . All this being said I think you have a clear call especially given the wild play V seems to be prone to. His range is just too wide to be folding especially when he reasonably has only only 1 combo beating you (KKxx).

Given the hands you posted folding the 3rd nuts on the turn seems lol.

Flop seems marginal in both spots. Esp. so if you are even thinking about folding turn. You also can't be deep if villain has 1 SPR on turn, your outs are small and most of them can easily be bad but when you hit them you can't go folding.

They're ~ 300bbs deep.

Regarding the hand, I'm getting it in vs the described V. IMO it's pretty relevant that he potted the 4556 as it reduces the amount of AA/KK combos in his range

They started deep then, they have a big pot now, but they aren't deep by the time villain calls closing the action on the flop.

This is relevant because if they were deep there are a few turn cards that villain can slow down that don't directly/immediately improve our hand ... there is also the possibility of bluffing given two more streets. None of that is relevant when there is 1 SPR on the turn and villain just auto shoves QJ (or even 100% of his range) no matter what card it is ... and we are left trying to work out if we have 33% equity as our only action.

I think you talked yourself into calling twice on the flop with a lot of could be's. And yes you were deep, which is why I think you should have folded that spot. You have the 3better leading into you and are way behind his range, and a maniac behind who you know pushes thin value. You are risking 300bb to find out if you could be good.

Now that you've hit one of your non nut outs you are realising that this spot isn't so good, so that just confirms why it's a fold on the flop. Given your read on villain and getting 3-1, this should be an easy call. But calling off 200bb in this spot sure sucks.

I think this hand shows has difficult it is to play deep stacked, as it is easy to build a big pot thinking you have lots of room to manoeuvre. But suddenly you realise you have passed the inflection point and are now in a world of pain.

PLO tends to do that. You go from infinite big blinds deep to facing an all in shove on the turn for all the biscuits

SPR on the flop is already just 5.7, so that isn't deep anymore. Absolute bb amount doesn't mean anything in itself.

That's right, but it's also not low enough to commit with top and bottom on this wet a flop. We're in no-man's land, which is why I think a tight fold is the best option.

but the BB turn into plastic discs and those eventually become bitcoins..

Against a maniac with this described tendencies i think it's a call.