When I was playing this game a year ago everything fast fast and normal. I stopped playing after caves and clifs update. The game was smooth, there was no problem in creative when flying at maximum speed, chunks loaded fast, loading screen when going to nether was less than 5seconds. After a year (right now) I wanted to start playing again. At first I noticed, that minecraft loading screen was slow, it took about 30 seconds to load, which wasnt normal. Then I created the world and it took more than 30 seconds to load. When I spawned I saw that chunks are loading very slow. I ran and saw that I ran into edge of grass, and there was empty chunk. Then it loaded. It was very slow. I created other world on creative, i flied and crashed in the air, then looked down and saw empty space, chunks where not loading. Then I builded a portal and the loading speed to take me to nether was about 30seconds, and that is very slow. In the nether chunks where loading slow aswell. So I tried to delete and download the game again. Nothing better. Then I bought iphone 8 (was playing on iphone x), i was thinking maybe my phone is slow or has a virus. On iphone 8 was the same, not better, not worse. I also tried to lower render distance, nothing changed. I tried maximum render distance, and i think it was a little but better but it was almost not noticable. I think its a bug on a new update. Please reply to me if other people are having the same issue.