The correct solution to that is to not have trash fights at all. D:OS2 did a great job of that and each fight felt meaningful.
I mean this is an after the fact transition though, so you can't really expect the same level of polish that DOS:2 had in terms of encounter balance.
Some impressions so far:
1) Each person seems to take turns based on initiative. It's calculated based on your dexterity, armor that you are wearing, and actions that you might take and bonuses that help that action. For example, two weapon fighting, which used to help recovery, helps your initiative instead, making you go earlier next turn.
2) Each action you can take aside from movement falls into one of two categories -- free actions and regular actions. Free actions are instant and you can do them in conjunction with any other action you might want to take, including other free actions. Good examples of free action are second wind, watcher abilities, turning on weapon modals. On the other spectrum are regular? actions, which you can do once a turn. Depending on the action they might cast instantaneously or take up the rest of your turn and fire off at the start of the next turn (maybe even more later on, IDK). For example, I created a monk/wizard hybrid, and his magic missle spell fired instantaneously, but the staff summoning spell started casting on the turn but didn't finish until the start of the next turn.
3) Movement seems to be on a separate system than actions. Both my characters seemed to get 10 meters of movement per round, independent of anything they did in the previous round except for things that increased stride (movement, essentially), or decreased it (hobble). Moving a lot did lower your initiative for next round though. Engagement is coded to make something stop moving when it encounters the engager, and it also triggers attack of opportunity when disengaging, so that's another way to stop movement.
Overall it seems like a competent, if not super fancy, turn based mode implementation. I didn't get a chance to participate in any of the more notorious battles yet so I don't know how dangerous things can get yet. It's still the same Pillars Combat, though, with the miss/graze/hit system, so on higher difficulties you do end up missing a lot, especially at the start of the game, which makes battles last a bit longer than I like. I think they probably need to increase damage a bit or lower health a bit to make the system a bit better turned for turn based mode. But it does seem like they made an effort to reduce the number of enemies in an encounter to compensate for the longer battles. Maybe they do more damage already? It's not easy to say.