Hey there, you’ve put a lot of detail in your post and I think you might find this thread useful when considering wiring etc.
I would suggest that the wires will outlast any other component in your smart home so if going wired, it is definitely worth planning. I am not sure which wired solutions are fully open source, and TBH I think that might me at odds with your other design goals … for what benefit? I went fully wired about 15 years ago using proprietary controls (www.idratek.com if interested. The support and quality of the hardware and software is excellent.) While the benefits of wired are reliability, low power consumption and simplicity (no VLAN) be under no illusion that the installation effort is significant. You can DIY it but it will impact your life. If you bring in trades to help you they may well struggle with anything too novel, or they will be a pro installer outfit and will be familiar with one set of technology more than something else … prob not an open source one. However you organise your cables, make sure it complies with the regulations where your live.
Finally I’d recommend splitting your control locations eg 1 per floor at least. I have 2 big ones (node0 ,1) and 2 small ones eg for heating (eg each radiator is wired with a centralised transformer supplying 24V via a relays to each rad). It will save a lot of cable and make it easier to manage.
Good luck!
J