More of an observation than a question -
I have two Baofeng GM-15 Pro handhelds that can each "kerchunk" a local repeater. This tells me the CTCSS subaudible tones for transmit are set correctly. But when transmitting from one radio, I could hear no audio from the other radio.
However
I was able to be heard by others using the same repeater.
Explanation - The two handheld radios were located too close together - moving them 10-15 feet apart made the audio clear from the second radio. So you can't sit in a car and check that two handheld radios are working with a repeater. Apparently the repeater circuits mute the audio when the slightest feedback is detected.