Just another jockey
You could select TA only for pairs / multiple work and TA/RA for singleton if necessary. TCAS logic is becoming exceptionally clever - google 7.1.
The TCAS trg instills the bottom line that RAs MUST be followed and within specific timeframe (5s initial 2.5s follow on).
It's not a cure all but increases SA exponentially, and if its installation prevents one midair then its money well spent.