Stalkers are using AirTags to track people. Apple will warn you if someone is tracking you with an AirTag, but only if you allow Apple to
track you — all the time, for certain.
(Tracker Detect surely works by telling Apple where you are — and
what more data does it send?)
That does not fix the problem, it just replaces one tracking system
with another.
Making the AirTag give a sound is a step towards a real fix, but it
should also give off radio waves that allow you to find it using a
portable radio receiver nearby to get a fix on it.
A real solution would be to require AirTag-like products to emit
radio waves that one could detect with some non-computerized receiver.