I love Aqara for all the sensors stuff, their products work good for me and are a breeze to set up with my son-off ZigBee stick.
I do use a door sensor on my mailbox as its still quite dark in the morning where I live and when the postguy delivers there wouldn't be enough light for it to trigger lol
Just to throw on some additional ideas: instead of a HA green you can get something like a HP EliteDesk G3 or Lenovo M75Q Tiny and run HA on that. You then have enough performance headroom for Frigate as your camera recorder even with machine learning based detection etc.
And you'd still have enough performance left to run something like Music Assistant 2.0
Regarding your question: yes I can look at the feed through my app at any given time
I use the RTSP2web application in home assistant for better latency, as direct RTSP streaming from the cameras has a delay of around 5 seconds.
I then just plugged that web stream into a video card on one of my dashboards and made a little dropdown menu for a couple preset PTZ points to quickly change to
I had Plex lifetime and still switched to Jellyfin as an open source and community driven project will always be better in the future compared to a commercial product
There is a huge difference between your house and a country.