Users are certainly very reluctant to drop into a command line, but in my experience if it is a true necessity for something they want to do, they don't actually have that much difficulty with it.
Yes, of course sideloading may still remain possible in such a scenario, but it would not be mainstream enough to sustain any kind of mainstream ecosystem of apps outside of the Google Play Store. Even F-Droid supporters have been worried that clamping down on sideloading could marginalize F-Droid even further than it already is.
Don't get me wrong, I agree that trying to restrict users from installing software of their choice on their own computing device is user-hostile, but in this specific scenario, users sideloading apps banned by their government, I don't think having to open a command line to do it would significantly shrink that userbase, which is already comprised of a small minority of particularly committed people.
But all of this is moot regardless, because AFAIK this doesn't extend beyond the realm of speculation.