Haha, well, y'know, it's become my favorite system to play games on so I try everything I can on it. A surprising amount of stuff just works!
I'll keep looking for solutions; maybe I can get it to work with Steam Proton instead and get different results. If that doesn't work out I'll wait patiently. :)
Edit: adding it to Steam, enabling Proton, installing the RTP, then running the game totally worked! I can play this with save files now.