im confused about ratings across different gamemodes

hi everyone!

im confused about the differences between rapid and bullet games.

despite having 1200 rating in rapid, i struggle to get past 700 in bullet. ive also noticed similar rating differences in my friends' ratings. 

so i did some research. i replayed one of IM Kacparov's 1m bullet games in a 15|10 rapid format. the game review showed that in the bullet, kacparov played like a 2900 rated, and his opponent like a 2850. but when I played the same game in rapid, the accuracy stayed the same, yet the evaluated ratings dropped to 1450 and 1350.

it appears that bullet ratings are approximately double the rapid ratings, this suggests that chess.com's game review factors in time, achieving high accuracy under time pressure is rated much higher than achieving the same accuracy in rapid games. this is done to balance the ratings accordingly.

ive observated that players with rapid ratings starting from 1500 dont encounter rating differences between rapid and bullet, but the majority of people with rapid ratings under 1500 do.

so my question is, why is there such a significant difference between rapid and bullet ratings for people under 1500. is there a certain rating threshold where these differences start to balance out? and do a lot of people experience similar discrepancies?

any insight or advice would be greatly appreciated!

thanks!