Tough spot. I'd definitely call all Q4 or better - he's probably shoving all boats here. J4 isn't great if you don't block the T as well, since the hands you're most worried about here are TT, QQ, and Q4. You're very rarely going to see JJ, so blocking it doesn't help much. I still think J4 is better than T4, even though the blockers are worse, specifically because it beats T4 and ties with J4.

Against a good player, I think you're right about only beating a 4xxx bluff, which you block. I'm leaning towards a fold.

in this, and in a lot of other low SPR spots where you're OOP and IP has very few natural bluffs, whilst the precise EVs of your three options are up for debate, one thing we can usually be confident of concerning their relative order is that chkcall will be the worst.

What do you guys think about going into check/call mode on the turn? I feel like going for 3 streets of value is little bit too thin on multiple bad runouts (A,K,Q) anyway.

could bet less on the flop on account of board texture