The answer to your question is no.

In theory, any router can be used to detect your pose, however, the characteristics of Wi-fi signal that led to this capability is also the reason regular routers setup at homes can't just be to spy on people: Wi-fi signal cannot travel very far through not just humans, but any objects with sufficient density.

So, unless it is a very specifically set-up empty environment, the Wi-fi signal will probably get reflected/absorbed by every furniture/decoration/wall in the room, and the signal will be much too noisy to get a clear for motion tracking. So, unless the interior is literally an empty room with bare concrete walls, your underground bunker is pretty safe from people, including Starlink, from spying on you with signals from your own Wi-fi router. 

If you are really worried, you can setup a package sniffer in your network and look for unknown large amount of traffic, as accurate motion sensing data will be pretty heavy on network resources.
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