Game developers should never use upscaling, develop everything at native 4K with 4K ultra textures, and for playing at lower resolutions the game can remove pixels for lower resolution. Similiar to how 4K recorded video looks better at 1080p than 1080p recorded video.

For framerate and GPU performance, we are now in the 4K capable GPU market and only getting better every 2 years. In 2026/2027 people will NOT require the top GPU for native 4K 120fps which means 4K GPUs are only going to get cheaper and cheaper, not for price but can start pairing a lower GPU with a 4K screen.

Upscaling is not available on older games, some of those are more popular in terms of favourites than brand new releases, and upscaling is inconsistent across games that have it.

The smoothest performance across a random 20 to 30 games will always be to only play at native resolution with no frame generation technology.