Would it be worth the hassle to get some chrome alum to make a hardening bath
The problem really isn't the hardening per se. It's the lack of a protective supercoat. Hardening the gelatin further (it's already hardened on x-ray film) won't make all that much of a difference.
Your best bet is to learn/harnass a process that involves minimal to no scratching. It can be done, but it's fussy, especially if you're using double-sided film. I had decent luck using single-sided Ektascan B/RA back when that was still made. By the time I 'mastered' it, I realized I had been investing loads of time in a material that inherently delivered poor tonality under most conditions. Moving to regular film like Fomapan felt like a huge relief - it just works!
Btw, when using double-sided film, you could just accept the scratches on the bottom side of the film and then strip the bottom emulsion when you're done. You can do this by taping the film to a surface, image-side down, so you can strip the backside. It's a little messy, you're left with an un-stripped edge and you need to be careful you don't get any of the liquids involved on the image side. It can work.
To each their own; I just didn't find it worth the hassle, especially on 4x5. Low-end regular sheet film isn't
that expensive in 4x5".