If your router doesn’t supported static IP reservation ... Just choose an address that’s different that all the others and hope for the best. You probably won’t

If your router doesn’t supported static IP reservation ... Just choose an address that’s different that all the others and hope for the best. You probably won’t be using a machine like this 24/7… Or assign one out of the static pool without the need for finger crossing. Never seen a router that doesn't let you adjust the DHCP range.