Basically there are different settings you can choose under highres for upscaling the images
Algorithim to upscale and make the image more detailed and higher quality
I did a few tests and saw how effective different ones were: There were a lot more tests, but I feel like these are some of the few that were the most effective
Original image (Latent Nearest)
Latent
Latent Antialiasing
Latent Bicubic
Latent Bicubic Antialiased
Latent Nearest
Latent Nearest Exact
None
Lanczos
Nearest
ESRGAN_4X
R-ESRGAN 4X+
R-ESRGAN 4X+ Anime6B
LDSR
ScuNET GAN
ScuNet PSNR
SwinIR 4X
Lollypop
4XNickelback
4XFoolhardyRemacri
4XUltraSharp
4XAnimeSharp