Correspondence players above 1800 on this site are generally quite solid. I’ve run into three types. 1) genuinely good blitz and bullet players who move fast, 2) serious correspondence players who use available resources to the fullest, and 3) cheaters.
I recently played two games against one of the first group. I beat him positionally and tactically with White. With Black, I sacked a piece overlooking that my plan to win it back five moves later would hang my bishop. Nonetheless, his rapid play caused some inaccuracies that allowed me to reach a drawn ending.
I never made 1800 in bullet, blitz, or rapid here on chess.com. I am horrible at fast time control.
At my best, I made 1910 USCF.
I did go from 1346 to 1821 in daily games in less than a year. then I stopped playing for 8 years. I am now around 1600 in daily games.
I'm surprised that a 1900+ USCF cannot get over 1800 on this site.
I can make all types of excuses
a) I didnot play for 8 years and am extremely rusty.
b) I have a completely new repertoire for white and black against e4 and d4.
c) I say I am going to study but I never actually do.
d) the majority of my opponents in daily are ranked between 1900 and 2200 and I lose a lot.
e) I am not consistent at all. I have won against multiple 2050+ level opponents and then turn around and lose to a 1200.
but the real reality is that I probably am just not actually a good player.