upscaler rename it to *.pth and copy into \ESRGAN or \RealESRGAN or upscaler path
orginal link:
https://openmodeldb.info/models/2x-classicalSR-DF2K-s64w8-SwinIR-M
but if you want real nice upscale... best for 700pix and lower -> use topaz gigapixel ;)