Trouble with /tmp on F35

So i have an application which requires many gigabytes of space on /tmp. tmpfs isn’t going work so i disabled it with systemctl mask tmp.mount and rebooted. /tmp is now on root partition and all good so far.

Then i created a separate ext4 fs and added it to /etc/fstab
LABEL=blah /tmp ext4 defaults 0 0

mount /tmp works as expected, it’s formatted and labelled correctly. Reboot, and the system fails to boot up.

[FAILED] Failed to start Userspace Out-Of-Memory (OOM) Killer.
[FAILED] Failed to start Security Auditing Service.
[FAILED] Failed to start D-Bus System Message Bus.
[FAILED] Failed to start Network Manager.
...

What am i missing?

Cheers.

(and yes i know the app needs fixing, but i just need it working for now)