Fed up with google/nest. Whats needed to switch to the unifi g4 doorbell?

So I have quite a few nest products in my house from before they where acquired by google. The thermostat, a few smokedetectors and the doorbell. They recently announcedthat their subscription would increase by 66%. For me that was the final straw.

So I started looking around and found the g4 doorbell. I am trying to get a good understanding of whats needed to get that up and running in my house. I see all those fancy pictures of home servers etc and I am wondering if I need that as well (probably because of local storage?).

Can you give me some advise on that? I don’t want to spend thousands of dollars but also don’t want to cheap out.

Thanks!