For me, anything 25 FPS or higher is 100% fine and I’ll be enjoying my time. I never play competitive online shooter games ever, though. All single player ones like GOW and the likes. I game on a 60 Hz 4k monitor. GPU is AMD RX 6600 alongside Ryzen 7 5700G and 32GB RAM. My games are set to meduim most of the time at 4k. Demanding titles are on low. Surprisingly, GOW and GOW Ragnarok are both set to ultra and I still get around 40ish FPS.
My personal minimum is a stable 40/s, which is roughly where I start noticing the lower framerate without paying attention to it.
With 30/s I need to get used to it, and I usually underclock (or, rather, power-limit) my GPU to hit an average 50 unless the game in question is either highly unstable (e.g. Helldivers 2) or the game is so light I don’t have to care (e.g. Selaco).