I got around to testing this today on W10 21H2, here's that data for anyone curious:
Original ISO:
5.47 GB
Convert to WIM, WimCompression 2 (default):
4.92 GB (7 minutes to export)
Convert to WIM, WimCompression 0 (none):
9.07 GB (9 minutes to export)
Note: when converting to WIM in NTLite the only modifications were to trim all intall.wim editions except Home (core).
For anyone wondering why you'd want to play with the compression, the gist of it is, if you want a faster installation of Windows then uncompressed should be better since the CPU doesn't have to uncompress the files first before installing them, but in other places outside of Windows Setup, such as while copying the files to a USB drive it will take longer since the files are bigger. There's certainly pros and cons in either direction, and I don't think either choice is superior to the other, it mostly just depends on your personal circumstances and the machines you are dealing with.