Hi...i have some remote devices connected to internet by a 4g connection so they haven't a pubblic ip and is not possible to connect by remote smartphone. I know there is a way to make it possible using a vpn whit an external pubblic address. I make a draw to explain it. So by smartphone i put into browser public address a.a.a.a:aaaa to connect to device 1, a.a.a.a:bbbb to connect to device 2 and so on and each devices is independent by other one. I'm thinking at a VPS whit CHR for VPN server and at some routerboard as a VPN client, and i connect my devices to mikrotik client. Can anyone help me about configuration?

You have to configure one SSTP server in your cloud CHR (or you can buy one routerboard and configure it to your home as SSTP server) with static ip address or ddns service,
then you can simply create on each mikrotik site one sstp client pointing to your sstp server and boom! just configure static router or OSPF and you are ready ! Just connect with your smartphone via vpn!

My idea is not use a vpn client on my smartphone.. my idea is to connect at my NVR simply put the CHR ip Addres:port
So if i want connect to NVR1 i use CHR_ip_address:10000 but of i want connect to NVR2 i use CHR_ip_addres:10001