Correct PC version of iTunes that will library share with iTunes Mac 12.9.5.5

Just repaired my PC iTunes playlists with massive, manual effort; thought I'd do it on the latest PC version 64 bit 12.13.2.3, which turned out to be a big mistake. I then discovered the last Mac version of iTunes (runs on Mojave) is 32 bit 12.9.5.5. That itunes version complains about my library and music folder based on the later PC version. Now I have to try to dumb-down my PC version to something compatible with the Mac version and yet that can accept my new PC library version. I'm wondering whether the incompatibility is more likely the version difference or the 64 vs 32bit processor version?