#1) I dont have a bunch of electronic gadgets to occupy all that space on my handlebar.

and over the past 40 years parts have changed..

in the 70s quill stems were the norm, hooking the bag frame of wire bent
so as to go over the bars, under the stem and over the other side of the bar..
You can still buy those .. Velo Orange got someone in Asia to make them, again.

Yes Threadless steerer tubes do offer the option of stacking stems , now I have a
Koga Miyata WTR, that I did that to, Bar bag mount R&K Klick-Fix. fitted on a 1" tube .

Other solutions, I used a handlebar adapter made to mount a waterbottle cage,
and used those 2 threaded places and some plastic spacers to mount the bar bag
for my longest bike tour I had shop access so replicated that in a steel stem, extra strong...
the bag does not pop off , but I was Wearing the important stuff,
in my Money-belt under my clothes.