It should work with any Android phone. You install RTSP Camera Server on the phone on the baby side. Configure it regarding the microphone use, video quality etc. I think that by default it also records and you may want to disable that, because it may fill up all the storage. To be sure disable battery optimization for it. I recommend enabling time-stamping, so you can see something even if it's quiet and dark, because with full screen VLC it may be confusing if it's still working.

Then on your client device you need VLC. You can manually enter rtsp://PHONES_IP:PORT every time, or make a shortcut and place it on your homescreen. It was certainly easier for my wife. To make a shortcut use the Shortcut to URL app. It's quite easy to use.

For it to work you need to make sure that phone's IP address will not change under you. Your router should give the ability to assign an IP to a mac address. If you have your own home DNS server you probably did not have to read all that.

All apps are free and without ads and seem to be a labor of love.