Only do this (don’t follow any other procedure, i cannot help you), or Why and how to extend ZRAM on L5. A revolution for Librem 5 stability! - #34 by riabenko (may be a better procedure):
I did on my 3 librem 5:
1.Reboot
2.Close immediately any running app because of autostart (or better: remove them from the folder temporarily).
3. And immediately in terminal copy past this in terminal:
sudo tee /usr/lib/systemd/zram-generator.conf.d/librem5.conf <<EOF
[zram0]
zram-fraction = 2
max-zram-size = none
EOF
sudo systemctl restart systemd-zram-setup@zram0