probably you already found a solution for a volume control pot with a lower profile. In this case, my 2 cents here is obsolete. But if still searching: maybe it would make sense to choose another option to adjust the volume, not by a potentiometer having a steady, continuous adjustement, but by using a BCD switch with several fixed resistors, more like a step-attenuator.
You yourself were the person that taught me the fact that for field day use rotary adjustments are NOT well suited. The rotary tune knob is enough exception from this rule.
And if there would be some sort of an AGC behind the audio (at least like in the fine old world of the ATS3x era), well then any adjustment of the level would be obsolete: only some rough level-setting-impedance-adaptor to suit different types of earbuds would be necessary on a set-and-forget basis. And this could be done by some BCD switch hidden somewhere at the side, either with primitive jumpers or with tiny sliders like the PC had to set the interrupt vectors.
Just thinkig loud. Fine project you have there again!
Merry Christmas and all the best to you all!