Se vuoi usare solo IP statico 192.168.1.93 con gateway 192.168.1.254, il file corretto e:
# /etc/network/interfaces
source /etc/network/interfaces.d/*
# Loopback interface
auto lo
iface lo inet loopback
# Interfaccia principale ens18 con IP statico
auto ens18
iface ens18 inet static
address 192.168.1.93
netmask 255.255.255.0
gateway 192.168.1.254
dns-nameservers 1.1.1.1 8.8.8.8
Applica le modifiche
ip addr flush dev ens18
systemctl restart networking