The A-10 is to some extent saddled with the problem the Harrier (GR versions) had in Uk use..the army loved them but at times the Air Force maybe had other priorities as to what they wanted to spend the money on and providing a long range artillery piece wasn’t one of them.
I know strafe attacks were impressive (we used to do strafe ourselves occasionally, albeit with a smaller caliber Gatling) but these days that sort of attack can be somewhat err, career limiting. Not so much because of the airborne threat from fighters, which as you say, could perhaps be suppressed, but because in theory in the A-10’s case it may not have the survivability against more modern MANPADS than the SAM -7 it was initially designed to cope with.
Certainly from what I’ve heard much effort went to improving the A-10s stand-off capability (at which point the Air Force started arguing in that case why not simply use things like F-16 for CAS, because they’ll get to scene of the fight faster), and AIUI strafe got reserved, so to speak, for use against lower tier opposition - now if it’s thought the Russian MANPADS are still p poor then of course there’s an argument for A-10 and the big gun in Ukraine.
All that said I’m not sure I’d fancy doing the trials in the field on a two way range.