Before you install the strictly confined version of MicroK8s, please familiarise yourself with the differences by reading this explanation of strict confinement.
Strictly confined MicroK8s is installed via the tracks that include strict in their name. For example:
snap install microk8s --channel 1.25-strict
If there are workloads that don’t run as expected under strict confinement Apparmor denials will be reported in the system logs. You can try to find what is causing the problem by using snappy-debug.
You can also try running the snap in devmode. A devmode snap runs as a strictly confined snap with full access to system resources and produces debug output to identify unspecified interfaces. You need to install the snap with the devmode flag:
snap install microk8s --channel=1.25-strict --devmode