I re-read the first post, and it sounds like you’re most important criteria be clear rules, and tactical combat that is NOT just two characters rolling dice until somebody wins.
Honestly, it feels like your more interested in some sort of tabletop war game that has thick Role Playing features. A game that is both.
Well, let me suggest Adventure Conqueror Kings System (ACKS). I’ve heard it’s good, but never played it myself.
Again, I’ll bring up Dungeons and Delvers Dice Pool Edition. It’s very clear, and simple rules. All stats and skills are dice from 1D4, 1D6, 1D8, 1D10, and ultimately 1D12. The D20 is not used. Roll your stat and skill, plus any of the many bonus dice from player ability talents to beat a GM set target number, or enemy defense number. Pick the best two dice results, add those two up, and higher number wins. It’s very clear rules, and very miniature grid square friendly. Some movement abilities are definitely meant for the grid squares.
The game is meant to be easy for grade school kids learning math, so ignore the kiddie artwork. It plays just fine as an adult game.
https://www.drivethrurpg.com/m/product/224154