Rerolls, strategems, etc

Can I say I absolutely love, love this game? The customization, the close combat, all of it. But playing it, I find that I do miss the synergy and combo engines you can get in games like Kill Team or the like where you can stack bonuses or penalties, or the tact. I know you can do something similar with some relics, but does anyone have any advice, or house rules, or are there rules in the deluxe .pdf for something like this that makes the game a bit more... combo-y or reactive? Am I asking for something counter to the design goals?