I wonder why this started to happen, it used to be MSAA which was awesome but now its crappy FXAA or even weirder and blurrier options.
I usually just inject SMAA and downsample for the cleanest IQ.
Deferred rendering, which like most games from 2010+ make use of, makes MSAA literally exponentially more expensive.
Best example these days is Mankind Divided, which is about a 20FPS per 2x sample drop.