Hoi!
May-be some idea from thread Reddit - Dive into anything ( google: “home automation sensor mat”)
I remember, that some time ago seen such mats also as products in HA-shops ( now quick search with negative results )
Also, there are some talks about microwave sensors . Actually they seems promising in words - in practice, may-be someone with hands-on experience may help. I personally just heard about them - not even deep-digged into manuals.
