You can run the following command to start Apache:

sudo systemctl start apache2

And if it fails to start or you want to know if it is running or not, run the following to know the status:

sudo systemctl status apache2

There seem to alot of things wrong there, how did you install Virtualmin? Did you use the Automated script or manual method? Maybe try Virtualmin - System Settings - Re-run install wizard.

Else you will need to correct the errors in the log. The fact its saying your missing Config variable points to a bad install.

Steve

You may need to get staffs help with this one. A normal install should work fine unless you have manually changed things. By the docs your OS is support using the standard script at https://software.virtualmin.com/gpl/scripts/install.sh is that the one you used?

Steve