Agreed. I would categorize myself as a similar profile to the OP: a nerd that has set up very complicated systems, formerly worked in IT as a desktop support and network administrator, and runs systems with multiple OSes in my home, but NOT a programmer and Home Assistant is one of the most difficult pieces of software I ever tried to use. The user interface is anything but easy. There is no useful documentation despite everyone claiming there is. The UI is pretty but the UX is garbage.

I’m running Hubitat and it works great. I have setup complicated automations with no issues whatsoever. Every few months I try to dabble with Home Assistant with the goal of moving over because everyone here preaches about it’s greatness, but every time I get frustrated, give up, and stick with Hubitat.

Which TV and which speakers/receiver?

With most modern TVs/Speaker setups this is possible without any additional hardware using HDMI-CEC (each TV manufacturer calls it something different for “branding” but it is all standards-based)

I haven’t kept up on it, but didn’t Logitech discontinue the harmony hub? Is it still supported in any way? for how long?

What is the ultimate end goal?

You probably aren’t going to find a “doorbell” that will seamlessly connect to a relay… as a “doorbell” isn’t designed to do that.

What you can do is find a wireless button and a smart relay and a way to link them together, that will probably need an intermediary (zigbee hub.)