Reserve IPs without router configuration access

Hello, im in a situation where i would like to reserve 192.168.x.100 for pve web, .101 for container id 101.. and so on. The problem is that my ISP doesnt give out access to the router config, so i cant reserve dhcp via mac addresses. According to email i recieved, the dhc pool is 2. - 254. I was thinking of solution and worked out that the router does ARP conflict check, meaning that is a .100 already responds to ARP it wont assign it. Would a good solution be to just reserve the ips 100-120, and then give them out to the LXC when it starts and reserve it again when it ends? WIth ip addr add./del Or am i just overcomplicating things, by the way, this is for my minipc homeserver running 24/7.