Even though I play it on my old low end laptop, I still able to get a stable 60fps on medium settings at 1080p (Linux) and the game is still gorgeous looking probably looks better than most if not all UE5 games released in the past 3 years.
Can't speak for you, but I'm still playing both pretty regularly. I still play GTA IV quite a bit too, and return to San Andreas often enough. Vice city is still a classic, but those older ones are just getting a bit janky, which is ok considering they are 20+ years old. All of these games were ahead of their time.
Definitely sets the bar pretty high, maybe impossibly high, for GTA 6