When you not have from your ISP a Public IP with unblock incomming traffic… then you must be a client of some DataCeneter/Cloud a VPN service who will connect your location and your cctv clients.
Last time ppl create a Oracle Cloud account and use free 2x vm who have limits 2core,1gb ram, 48Mbps and HowTo is here but you can create a vpn server at CentOS/Ubuntu and that way not use CHR with upload limit as 1Mbps.