Yeah, as said above, that’s for a single file, not the entire thing. I was just being completist when mentioning it - I’ve never had an audio file that big… even when someone sends me something that’s 192kHz, 32-bit!
You don’t need any software to convert between the two OS-es; the files will work on both. Just format the drive as FAT32 - in Windows it’s visible in the format dialogue box, can’t remember where it is on a Mac, but once it is then you can just copy the entire song to a folder on the drive (if you’re not sure where all the audio files are, use “backup project” and put that on a new folder on the drive), and then open it on the PC.
Any third-party or Mac-only plugins you’ve used won’t get loaded, but if it’s all steinberg or cross-platform free stuff you’ll be fine.