Thanks @magtuired, @Stephane for your quick replies!
After posting the op I recalled that I should have added some parameters to the kernel boot command line. Adding apparmor=1 security=apparmor seems to have resolved the issue:
cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-linux-zen root=UUID=3abad4a5-5c06-417a-b356-45004fe96e73 rw resume=UUID=e5c0
bebe-3ab0-4474-9b40-5df3116b236a resume_offset=1085440 apparmor=1 security=apparmor loglevel=3 nowatc
hdog
After reboot:
systemctl status apparmor
● apparmor.service - Load AppArmor profiles
Loaded: loaded (/usr/lib/systemd/system/apparmor.service; enabled; vendor preset: disabled)
Active: active (exited) since Wed 2020-09-02 11:20:11 CEST; 3min 14s ago
Process: 260 ExecStart=/lib/apparmor/apparmor.systemd reload (code=exited, status=0/SUCCESS)
Main PID: 260 (code=exited, status=0/SUCCESS)
Sep 02 11:20:05 vostro-plasma apparmor.systemd[260]: Restarting AppArmor
Sep 02 11:20:05 vostro-plasma apparmor.systemd[260]: Reloading AppArmor profiles
Sep 02 11:20:11 vostro-plasma systemd[1]: Finished Load AppArmor profiles.
Warning: journal has been rotated since unit was started, output may be incomplete.
aa-enabled
Yes
I will read further on the link that you have posted @magtuired, since both you and @Stephane are mentioning a couple of other parameters to be set.