My router has a pretty descent firewall so i feel like it should be safe? Maybe. Obviously I won’t be signing into any online accounts or anything like that on the XP machine. Is this a bad ideas? Obviously using Windows in general is a bad idea but I’m sort of limited by the hardware here.
macOS can read FAT32 and NTFS just fine. I’d put the drive in an external case and copy it over. You could also use PuTTY tools to copy from Windows using sftp (on macOS). I think macOS also offers samba?