Data keeps getting deleted

When I created new world, I started playing it and then when I left and went back in the world. My player data got deleted and I had to do all over again. My friend found a way to fix it by copying the world then going back in, and it will be fixed but he needs to copy world every time he wants to play that world. It wasnt happening until update with bug fixes (1.19.63). Please fix this. Thanks.