File-diffing cannot be skipped. It’s one of the primitives of how Netlify works. We check our CDN or the SHA of all your files. For any of the SHAs that are already present on Netlify, we don’t upload that file.
So, this goes without saying, higher the number of files, the more time it will take for diffing as we need to then compare the SHA of each of those files to detect which file we actually need to upload and which already exists on the CDN.
No, we upload the files as they are, and apply any kind of available compressions while serving it.
No special recommendation - just make sure all kinds of post-processing is disabled in the site’s settings and form detection is disabled too.