It was Final Fantasy Tactics for years, and Frostpunk also held the top spot for awhile. But if I reduce it to measuring dopamine hits, I don’t think any game is better than XCOM2 with the LongWar2 patch.
Rather than the 20 or so odd missions in the main XCOM2 game, the core mechanic of LongWar2 is a guerrilla/political-terrorist simulator. Most of your 100+ missions you’re just trying to steal enough resources to keep your organization alive. Occasionally you’ll get a chance to sabotage, and missions of actual strategic importance are even rarer. The stealth, then smash & grab, then holdout against overwhelming odds until evac comes - mechanic of the “steal resources mission” you need to repeatedly do has led to the most exciting & fun game-play moments I’ve ever had.
It’s like they discovered the formula for the most fun mission possible in XCOM2. But instead of making it “the final mission” they built a new game with this formula as the core mechanic of the campaign.