It's not really complex
i agree you could ditch homeassistant but a MQTT server in your home come's in handy when you start to tinker around and want to do more

. The HA server just makes it nice and automates a general interface to control switches and read out the status of it or other sensors

my partner loves the camera dashboard that shows all camera's at once and is still able to control the other bits and bobs (lights, locks etc) but not losing the real buttons around the house (for example)
No programming skills required to automate a
lights on action when the sun goes down.....not even if you want to turn on your lights 45min before it goes down. want to have a push message on multiple phones when the garage door opens? Sure give me 2 minutes!.. want a snapshot of the camera in it? Want a link to the live stream when you click the push message? and so on
You can probably do this with a batch script but about 6 dollar for a relay and an ESP that comes in a box and is automatically discovered in your web interface... this beats writing code over and over again

We don't have to reinvent the wheel every time we have a new project.
A sonoff is basically the same as what you suggested but then without the need to program or solder and smaller... possibly safer too

you have alot of models of it even ones that replace your light switches.... but they also make them "smart".
BTW: Zoneminder is also a integration that can be enabled in HA so you can view your garage camera and make buttons to control the garage door for example. the Sonoff also integrates.... i guess you can say, seamlessly.
But when it comes to the question... Checking a garage door with a camera might not be the way to go.
I think you would be better off with either of our solutions, so you either buy all hardware separate, solder your way through and are not afraid to program a bit (and possibly learn to program) or you buy ready made boxes at 6 dollar a piece and invest some time into learning to setup Homeassistant (takes about an hour maybe two if it's your first time) and let devices be detected themselves when you connect them. (flashing the sonoffs with custom free software is easy too) I know what i would choose
I'm just glad that i could help you pankaj13
No, i'm not sponsored by either. i'm just a fan of the products as i do with Zoneminder. i would also defend it above blue iris etc... 