forget Realergsan - classical is the best

upscaler rename it to *.pth and copy into \ESRGAN or \RealESRGAN or upscaler path

orginal link:

this is worth a try:
/>and thats very good for faces (8x_NMKD-Faces_160000_G)

if you want real nice upscale... best for 700pix and lower -> use topaz gigapixel ;)