https://www.freedesktop.org/software/systemd/man/systemd.mount.html
x-systemd.mount-timeout=
Configure how long systemd should wait for the mount command to finish before giving up on an entry from /etc/fstab. Specify a time in seconds or explicitly append a unit such as "s", "min", "h", "ms".
Note that this option can only be used in /etc/fstab, and will be ignored when part of the Options= setting in a unit file.
See TimeoutSec= below for detailss