The question is unfortunately not a hypothetical. The SSD that I installed FF14 on is dead or close enough to it that it might as well be. I'm not sure what is the significance of Steam's notice that the install folder can't be changed, so I'm wondering if I were to simply install a new SSD in my computer and install FF14 there, would that cause issues?

Probably relevant additional information: my primary SSD, where Steam is installed - where I believe my game's local save data/profile configuration is located - is still perfectly functional.