nmcli con down ens192 ; nmcli con up ens192
might also do the trick (i.e. push new settings to kernel).
Seems redundant. The
nmcli con mod ens192 802-3-ethernet.mtu 9000
should ensure on its own that proper section of the correct file has the “mtu=9000”.
But, if proper section of the correct file already has the “mtu=9000” (via manual edit),
then you don’t need to write it with nmcli (again).