Raising the river was very foolish, calling or folding are both a lot better. You should have bet the flop small. Betting the turn was okay, but you should have bet smaller and folded to the check raise.

I'm never folding. Potting was somewhat bad though, that I can agree. What I thought was that I should have raised river to something like 25$ for value and folded to a shove. I bet the flop most of the times, but I check this also some of the time. Given that we are deep I should actually be betting the flop yes.

Villain is on the tighter side

I'd rather bet flop then, he has a strong range and would be calling at least one street in such texture with most of his range, I think sizing around half pot or less is nice, so he can even try to exploit bluff raise us and maybe 2nd barrel turn on that run out, on which I'd be calling again cos there is no FD now and I prefer to keep his bluffing range.

Although as played I don't see why raise the river when he pot, the raise itself would have got hands like KK/QQ to fold (which is already bizarre of thinking that he might value bet these when he could x/c river sometimes, lol imho) and your size would make a possible (but least expected) AA to re-think it and more often fold, that's why just calling is fine here with the second nuts.

Maybe it´s good to change the perspective – what hands could the 18/8 bluff and what could he bet for value OTT and OTR?

When he has a valuable show-down hand he x-call OTT too and let you do the betting - keeps your range wide.

OTT: x-raise on a 3rd "4" – (which could be categorized as a "blank") looks really suspicious to me and capped his range – And he changes his line on that card, from x-call to x-raise.

I would prefer keep the pot under control and call down, or probably fold OTR.