To answer the last part of your post:
So far my experience is that the RCS-iMessage feature is working (or not) depending on the Apple user's provider. I'm on Android with a "cheap" provider in Canada and RCS-iMessage work with my iMessage contacts that are on major providers but those on cheaper providers don't work yet.
So if you are on Android and your basic RCS works you should be good.
I have had Zwave Yale locks for almost 10 years now and am pretty happy with them. I have the assure SL (mentionned in another comment) on 3 doors right now and they are rock solid.
The battery is reported to Zwave but you will also get some beeping and flashing on the lock itself when the battery gets low, so even if you don't see it in HA it is hard to miss and end up with a dead battery.
As a side note, I always bought the push button variant of those locks and stayed away from the touch pad version. Living in Canada it seemed like a bad choice to deal with touchpads in the winter with the gloves and snow possibly melting on it.
S'ils ne sont pas géographiquement bloqués en France vous pouvez utiliser ceux du CIRA. Ils ne devraient pas être censurés. Reste à voir la latence transatlantique.
If you are using zigbee you should check Sinope Sedna Walter valve with the optional water flow sensor. It is supported in zha using quirks from claudegel on github.
Just make sure you select the ZigBee one since their WiFi one need their proprietary hub to work.
Canadian here who used both small and big providers with pixel phones (3, 5 and 7 pro) bought directly from Google (not financed through the provider).
Not all smaller providers provide 5G but they all have LTE or LTE+. I had 5G working with my Pixel 5 without issue when I was with one of the large providers. I'm with a smaller provider now on my Pixel 7 pro and have no issue connecting to LTE(+).
But, you also mention the Pixel watch. I never used a watch with a sim card and I have to say that it is not always clear from the provider's website if they are supported or if they will provide a esim for them or not, and at what cost. This is something that looks a lot more straightforward when with Apple than Android.
AKA a rocket stove
I am doing this with my personal and work laptops. I have two dell docking stations and a KVM to switch between the two.
It will work, probably not well. There is a ton of factors to take into account.
1- When switching the KVM input, depending on the KVM, the screens just get disconnected, meaning that the screens get re-detected each time you switch. Sometime it works well,sometimes not. Your laptop may also enter sleep mode since it is closed without screens attached. You may have to open it and press the keyboard if the USB from the KVM and docks are not re-detected.
2- If you use Displayport MST to connect your screens you have to make sure both the dock and KVM will support it.
3- When switching the KVM USB also gets disconnected and reconnected, it can be problematic with your dock, also see end of point 1
I have both high quality (and too expensive) docks and KVM that I took time to research and it works ok most of the time but still glitches. The docks and multiple screens add complexity to the setup and fail points.
If you go this way you will want to take your time and make sure all the pieces work together, I would steer clear of cheap Amazon stuff also.