Hello,
Yes there are 2 possibilities.
1. you activate the cloud access on your UDMP and then go to your UDMP via unifi.ui.com.
https://help.ui.com/hc...

2. you connect via VPN to the network where the camera is located. There are many methods. The VPN of the UDMP or my recommendation "Wireguard".

The easiest is cloud access, regardless of the security aspect.

Yes, that's not a problem - there's the Unifi Protect app for mobile phones, so you can access the videos from anywhere with a corresponding cloud account. Or you can use local users and set up a VPN.