KQs is a very strong pocket pair, in my opinion.
I don't think so, but depends a lot on the overall circumstances of course
KQs looks nice, but when you go all-in, you would have to consider which hands are likely to call your all in. You aren't favourite against any hand that has an A and any 55+ pocket pairs:
Source: https://www.cardplayer.com/poker-tools/odds-calculator/texas-holdem
Of course you might also get called by KJ, KT, QJ etc., where you are strong favourite, but more often than not, you will also find yourself up against AK, AQ, high PP, where you need a miracle then. But each players has his own style and some lucky charm hands he likes to play, so there is probably no right/wrong here. I would like to see a flop first with KQs unless I am short-stacked, desperate and have to gamble
(...) but not from @FOMA, who, based on my observations, usually starts playing only with good cards, and when he goes all-in pre-flop, you can bet he has something extremely good.
Yep. But with <10BB you will also see non-premium hands then just like from every other tight-ish player.
This is the interesting psychology with Poker - reacting to aggression and being aggressive yourself. You folded QQ in a good spot and had a Hail Mary all-in with KQs in a (I think) bad spot. 
You fold better hands than he has, but what can you do; the power of chips 
