I think it comes down to developer skill more than the engine itself.

There are a few indie games that run great and you wouldn't even have known they used Unity until you looked for it. The Hollow Knight games and Ori games are well-known examples that even manage to run on the 2014-era pile of underpowered crap that is the Nintendo Switch. Even some 3D games like Gunfire Reborn or Risk of Rain 2 (before Gearbox took over) run well on older hardware.

Shitty devs with better engines can still produce horrible, unoptimized games. More alternatives to Unity are great, but we also need devs who aren't pushing out half-baked slop.