I get the feeling that some on this forum are using the term “TCAS” for any traffic awareness system.
I would be surprised to see TCAS fitted to anything smaller than a turboprop or a top end turbine helicopter.
There are some very good traffic systems on the market, the smaller ones can be fitted in the smallest of Aircraft.
My one request to people contributing to this forum is to properly refer to the system you are talking about and no use TCAS as a generic term for any traffic system