MMX reused the MM base design with support skills or debuff skills that last only one turn and it's a choice to support/debuff/action at each turn, it's rather special but effective.
Gloomhaven, it's cards and complex in my opinion because of the attrition system, but it's grid based, not really a good base for a MM like system. The attrition system is deeply linked to the design of strict missions, it should not match at all a RPG somehow open, more one Hub+missions based, and even then it would be hard to make fit the attrition system to somehow longuer missions fitting more properly a RPG. I didn't finished Gloomhaven because of perf problems but I don't remind it's somehow a classic cards battler, anyway the grid/attrition system makes it very special for cards games.
I thrown cards games randomly and because it seems a design approach more open to fresh ideas, and I can see the positive it can add in turn based by changing constantly the context at each turn even if partially. But for now I didn't dig much.
I played some multi rows system in such types of combats, if I remind well Wizardry was multi rows even if not showing it. I never felt it was adding a lot. I don't have any single idea or tracks to improve such combats, again, if I enjoyed overall MMX combats (more than those of BT4) it's only because of the numerous ambushes and multi fronts combats.
Age of Wonders series always tried mix tactical combats with 4X, but in a campaign combats haven't enough diversity, hence play many or even all combats auto makes sense. Combats system as MMX have one positive in general, allow a rather fast resolution, so you can have more combats to fill a bit more your world. But if the combats are not enough deep and varied, for me, it's now still hard to play long, that's why attempts to replay MM3 or MM4+5 always failed. Some old JRPG had even more basic combats, the management was more meta like manage consumables along many combats. It leads to a question, why not have some auto combat system option like in AoW series? But Im' dry on suggestion on some meta gameplay above an auto combat system in a RPG context.