I ended up folding after thinking for about 30 seconds. I basically tried to decide whether he would give me credit for a flush here which is basically all I have when I raise this river. I would just call a lot of my combo draws on the flop probably in position which I'm sure he doesn't know. I'm also calling him down here most of the time with like AJ+ and not turning these into bluffs hardly ever, which he also doesn't know. I also have almost no hands in my range that get to this river this way and want to bluff other than straight draws that picked up spades on the turn, that's literally it (which he doesn't know). Overall all the pieces were perfect for a bluff imo, if I had any history with him at all or he had watched me play for more than a little while, I 100% would have tried this but without more info on him or knowing that he knows anything about me, this bluff becomes pretty marginal which is why I opted against it.