Happy New Year Joe!
Setting up a R-Pi Home Assistant to control your smart devices should follow a few key, up-front credos (much like using any IoT smart device and/or running a server/NAS) on one's home network:
Uplift your home network (if you haven't already done so...) to create an IoT isolated wireless network to keep all the gadgets off your primary home wireless trunk.
You can always deviate from that as things branch out but it's good to start thinking narrowly minded or guard-railed to kick things off.
Create all new accounts for your IoT gadgets, in terms of new email "pinning" - and migrate all the devices to those refreshed account(s) & check that it worked. Makes the most sense to have a common 'cornerstone' email account for gadgets - from the beginning. Who you pick to serve that email account will be personal preference. Believe it or not, Apple is a good way to go for that - - out of the majors. They preserve privacy much, much better than M$ or Gaggle and you don't need to own Apple devices to use it. Google, I mean Gaggle, is the worst - as I am sure you already know!
Obviously, you can steer clear of any of the prominent providers and go with Proton or whomever else...
Run your Pi Ethernet hardwired (to a router/switch) and I'd recommend you keep it (the Pi rig) close to a main computer that is also hardwired; this avoids having to log into the IoT dedicated WiFi network you've ginned up to host the gadgets. In other words; set things up to be able to talk to/control the Pi remotely over wire - if you envision needing that level of dominance - long term.
When you do have to log-in to the dedicated, IoT wireless network - do it with a deprecated phone, tablet or computer. Something you can assign to IoT wireless management duties that isn't tied to your primary devices!
Those are a few of the top-hitter suggestions I can make...
Have fun with this project Joe!
