I know it needs some work on curves etc but I feel like if I'm only getting OK scans, it's hard to put the energy into post pro when the result is only going to be so-so anyway.
To be honest in cases like this I often "auto-tone" it at least in PS, that function actually has gotten really good.
Make an action out of it like "resize to ....px > auto-tone > save" and automate (batch-process) the whole folder with it and it's a super quick / almost zero-effort quick remedy..
I know it needs some work on curves etc but I feel like if I'm only getting OK scans, it's hard to put the energy into post pro when the result is only going to be so-so anyway.