Meanwhile i do agree that these threads are mostly pointless, they're good if someone is using stupid sensitivities without knowing it, usually way too fast (under 10cm/360)
Anyways when it comes to your post, monitor size doesn't change csgo sensitivity and neither does resolution. The distance from monitor sounds even dumber. In fps games sensitivity is calculated in 3d matrix where pixels don't exist, rather degrees or more accurately radians. So basically if you don't have mouse acceleration on, your mouse always takes exactly same amount of distance to turn 360 degrees in-game, whether your monitor is small or you're sitting a mile away from it.
And when it comes to "best" sensitivity, i think 30 - 40cm/360 is pretty darn versatile. If you go slower than that you start gaining consistency and if you go faster its easier to move, especially noticeable in surf maps or when dodging flashes. In terms of dpi*ingame sens thats about 1000-1400, noticeable pro examples are f0rest with 1400, s1mple 1236 and scream with 1000. Most "arcade" shooter players also use around 30cm, such as ninja on fortnite and its the average value on overwatch and quakelive amongst pros, so its good value if csgo isnt the only game you play.