I need to take at least an intro Carbine course and need to be able to practice on a recurring basis.  The range we use for handgun practice can't support centerfire rifles, only handguns and 22lr rifles.  Of course we have public ranges for bench shooting, but I need to be able to work with a sling, work reloads, etc.  Cost is not a major consideration since if I buy a 15-22 in California I'm going to pay sales tax and DROS fees which significantly offsets the price difference between the two options.  I understand the 22lr uppers can be a bit finicky, but I'm willing to work the ammo problem and generally clean my handguns after every 300 round practice.  The light weight of the 15-22 is definitely a minus.  Any input would be greatly appreciated.
Rick

my CMMG dedicated upper has been flawless.

I did go with the CMMG upper.  Probably cost me $100 addition, a bit more if I buy BUIS for the CMMG, but I believe running the same lower is worth a lot.

Look at CORE rifle uppers too. The use CMMG action as well. I have one and love t. They have some different rail options than CMMG.

I went with the 15-22, you can add weights to the rifle if that is your concern but it would probably not be worth the effort.
I got .22 versions of my pistol and rifle just in time for the great .22 ammo shortage.
I now have blowback Airsoft versions of them, just hope they don't have a BB shortage.

Google "AR .22 conversion problems" and "15-22 problems", might give you a clue which way you want to go.

My CMMG upper also eats anything you feed it.  It just flat out runs.  The Taccom upper I built is more finicky with ammo.

I was in the same situation and went CMMG, have been very happy.