Shelly Gen2/3 BLU range limitations?

Hi there,
I am a keen Shelly user and have found the BLU range in particular to be extremely useful around home for various reasons but mostly being wireless and battery efficiency.
I am thinking about building up another Home Assistant system at my company premises leveraging the same Shelly BLU motion, door/window and button technology but wondering if it would work with the following in mind:
1.) The HA server will be stored within the main office building so I would assume the BLU devices in the immediate vacinity should function fine via the bluetooth proxy.
2.) There is however 5 outer buildings and a warehouse to the main office building which I I would like to equip with these Shelly BLU devices. WiFi signal is good to each of the buildings with seperate AP’s to each so wondering if placing a Shelly Plus 1 enabled as active/passive proxies would allow for these devices to all communicate back to HA ?
3.) Assuming the above is possible the last question would be if there is a limit to the amount of bluetooth devices I will be able to connect to a single instance of HA using this method. e.g. if i had a 1000 bluetooth devices would the system cope with it if HA is built on decent hardware ?