Ok, I solved it.
I found somebody in a similar situation to mine on unix stack. (I'll try to paste the link soon)
The solution that worked for me was to have fstab with the HDD set to auto, and then to add this rule:
/etc/udev/rules.d/98-usb-disk-mount.rules
ACTION=="add", KERNEL=="sd?[0-9]", SUBSYSTEM=="block", RUN+="/bin/systemctl start local-fs.target"
Statistics: Posted by luckyluca — 2026-01-30 16:35