realm has lags, and from time to time crashes and goes back to the last backup

Good morning, I created realm in mcpe, at the beginning everything was fine but later after a week it is terribly jamming, it is also jamming with my colleagues, it is jamming the most when I ride minecart, we defeated the end dragon and it is more and more jamming. sometimes he crashes us and goes back to the last backup. please help . jam most when many people are sitting on realism Additional questions: can you set more people to play on realism because 10 people is not enough for us. All players are from Poland