I'm not sure exactly what else you'd expect from a driver parachuted in from F2 on Saturday morning to achieve. His pace was good for the amount of time he's had in the car. He didn't destroy the car, or break any rules, or even look like breaking the rules. He qualified well and he made up positions in the race. What else do you want?
I think the 10 implies that they could have done no better in the circumstances. Not that nobody could.
I think everything you described is a performance worthy of a 7 or 8, not a 10, which is where I take issue with Bearman's rating even accounting for the circumstances. He finished in the position I'd more or less expect a reserve driver to finish in that car given those circumstances, and meeting expectations is not a circumstance in which I'd award a 10.
To me, a 10 would've meant finishing close to Leclerc or challenging him for the last spot on the podium—the kind of performance that would leave no doubt he was a future WDC, not one that leaves that prospect ambiguous. It's all subjective anyway; I tend to think a "10" should be reserved for legendary performances and I wouldn't describe Bearman's performance as such. It was a good job but to me that's all it was. For all we know Zhou has put in performances Alonso couldn't even match some races and only got something like 15th for it, totally ignored, and probably given a 7. I guess if you can't possibly know how good a drive actually was it's better to be nice about it, but that sort of makes all of this a bit silly and that's really what I was trying to call out—opinions and assholes and all that.