1. every player has a different limit, aka dexterity, some players cannot even play with anything higher than 2 sens / 400 DPI whereas some can play with 4 sens / 800 DPI, etc.
2. no, 16:9 is better in general because "stretched models" are a placebo, it's just an illusion that they are bigger whereas the reality is they aren't, the speed is a disadvantage lol, you have less time to react and you often get peeked so fast that you can't even react (aka XANTARESPEEKED), many pros don't "agree", they simple prefer 4:3 because they have been using it since 2008 and are used to it, not sure why it's still the thing to use 4:3 but it's just a stupid trend lol (similar to how everyone copies pro settings...)
4. we are talking about pistol rounds, obviously it is useless on buy rounds etc., but on pistol rounds it's superior to the usp/p2k, it's inaccuracy & damage are just slightly worse than the usp's but it has a bigger mag, more bullets and most importantly - less recoil AND better running inaccuracy, which means you have a much higher chance of run and gunning = better for pistol rounds
5. this is a common misconception, the mac-10 beats out the AK in every situation apart from long-range (and possibly medium-range) CONSIDERING it costs less than half of what the AK does, it's effectivity/price ratio is insane compared to the AK, close range it destroys the AK and even medium range a lot of the time, if it's truly your favorite SMG then you probably use it a lot which means you should know this... as a fellow mac-10 enjoyer I always buy it on buy rounds because it's just so OP
7. yes you can, you mention "no comm bots in mm" but who actually cares about mm? if you play faceit (preferably in europe), at around the 3k mark you will most of the time play with players who's comms and teamplay are good enough for you to understand what you might be doing wrong in that regard and learn from it, after that you can just learn from pro games and this should be really ez if you are not completely dumb af, it's up to you if you decide to act upon it... funny how you cherry-pick bad players like Kyojin, I can use the same logic and talk about ZyWoo, Bymas (who has been given a lot of praise despite his not-so-great rating), ropz, etc.
8. yes, I sort of agree with this, without personal experience (hah, get it) regarding LAN XP, I cannot say what the truth is but I do believe that at least to a certain degree LAN XP is actually important