Neverending problems with Linux

Just a random thought -- you've apparently been making a few network changes, plugging & unplugging cables, etc. Windows is horribly notorious for switching the Network Type back to Public again, effectively disabling file sharing. I'd give that a look and ensure the network type is Private.

I've done Samba sharing on the Linux machine, mapping that as a network drive on a Windows office PC. This lets you save gcode files from your post processor straight to the machine hard drive, and might present fewer issues than trying to keep file sharing working reliably on Windows. But it seems you might have tried this and run into issues, perhaps due to your outdated Debian version.

i had nothing but issues setting up network file sharing and ultimately started using syncthing which has worked flawlessly for me, i link 3 machines running linuxcnc and 2 pc's i run fusion360 on and have setup a foldershare for each machine that the post writes to and automatically updates to the linuxcnc machine file. it just works and i haven't looked back, setup took me less than 10 mminutes including installing on all machines and setting the post processor output folders, may be an option for you?

for windows installed here:

syncthing.net/downloads/

for linux, install is just temrinal command:

hope this helps!

I made a small video demonstration here: