Does anyone know if Fedora 28 still supports route-interface files?

I created a network connection TEST without a default gateway. Then I created a file route-TEST in which I put "default via dev ens33" and no matter what I try, the route is not added to the routing table. Not after network restart, not after bringing the connection down and up, not after a reboot.

If do it via nmcli so it is added to ifcfg-TEST, there is no problem.

Every manual and instruction I can find says this should work but it doesn't and I can't figure out why.

Any input would be greatly appreciated.