Earlier I was playing someone who had the following tendencies: very low cbet at 20%ish, would raise turn leads a lot, and vs flop/turn checks, he would bet turn and overbet river a decent amount. I found that he was overbetting with a depolarized range, having once run into a turned tptk and once into a boat. I'd like to get people's thoughts on a few things:
-how do we counter someone who raises turn leads a lot? I don't have a hand that often, and felt like when we didn't lead he would make life difficult on the river. Also, if he's overbetting a depolarized range can we consider sometimes minraising vs his overbets?
-what kind of spots are good to start donking vs. players who check back a lot? I'm aware of some of the more common spots like betting a wide range including draws and often tp+ on wet boards but vs someone with a cbet of around 20, I feel like we should be donking more. However I have no idea what kind of spots to pick. For instance, on a QT2ss board, what kind of hands can we donk vs. this player type? What about on dry boards?

As an overall strategy I'd donk my usual check/raising range, some of my check/calling range (mostly the portion that is happy bet/calling) and sometimes the top of my check/folding range OTF. If your concerned with balance and the weakness of your checking range, I'd mix in some checks from time to time with your stronger hands like TPTK+ and also checks with draws with showdown value.

If your opponent is balancing turn checks well then there isn't too much you can do about it. You really need to get some reads and recognise certain spots where villains are raising turn to see a cheap showdown, in which case you can 3 bet the turn or call/donk the river depending on what you want to achieve.

I would stick with the donking on wet boards and prob overbet donk the turn a lot. Or if we both check back flop overbet lead the turn etc. If his range is depolarized its weak a lot and he will play his range face up to raises usualy,we can shove on the river also, just depending on villians calling tendencies.

We can also c/r turns more where his range is weak. Say we donk bet or c-bet a wet board with say A5s board; 8c7c4s we c-bet villian call, turn is 2s we can check here because villian will bet his whole range here as he either has a draw or a weak made hand with little SD value.So we can c/r here and shove river or he will also fold the turn sometimes to, and if he calls we dominate a ton of his draws and we still have good equity and good FE on the river.

I would try and make villian polarize his range more and play his hand face up and get him out of his comfort zone where he will not know what to do and make mistakes.

IMHO first question you need to ask yourself is: "what does his line mean?" and "what range of hands he's doing this with?". Well, If he cbets 20% and c/raises turn with depolarized range this would mean to me he takes out all his flop hands ppl usually cbet with and c/raises them OTT. So if the flop is K27 and he holds KQ/AK/KJ he's likely to check it and c/r OTT for value. Also if he turns something good he c/raises it obviously. Adjustment I would take would be to take hands that can't stand a heat OTT to the showdown instead of thin value betting. This applies to very weak TPs and worse. Minraising is a terrible idea in my opinion because his range is most likely thin value hands and/or draws (although u don't know how he plays draws OTT, do you?). Once u start checking turn more often u have to find out how he reacts. If he bluffs river a lot or not. You should get the idea of his strategy pretty quickly after seeing several rivers and his play. Also because u start checking back some weak TPs ur range is protected and u can call him down very easily OTR a lot anyway.

Donking strategy depends a lot. First you need to see how he reacts to it, then when u know this post it in the thread . By default I'd start donking dry flops with air, hands for value and draws (the more he folds the weaker draws I'd donk).

Call much wider PF. He's basically letting you see a 4 card flop with the added benefit of knowing he doesn't have the top of his range. Generally speaking, OTT I would lead with a range that can 3b for value, or 3b as a semi-bluff, and hands with marginal equity that don't want to c/c. His range is probably capped OTT unless you think he's checking back monsters alot, if that's the case then CR his 20% cbet's alot, since that range is now much weaker.