The game is really slow at startup, at least in my world. I already found MCPE-62708, it describes my problem, but however, it is only for minecraft PE.

steps to reproduce:

1. create a new world
2. stay there for 5 minutes
3. set the render distance to a value so that the fps is round about 15 on your computer (I hope that makes it reproduceable, for me, this value is 14)
4. close the world and everything that has to do with minecraft
5. restart minecraft
6. restart the world
7. look the first time for the fps
   # wait 2 minutes
   # look the second time for the fps
8. wait 3 minutes
9. look the third time for the fps
10. close the world, but not minecraft
11. reload the world
12. look the fourth time for the fps

what I observe:

first time: 1-3 fps, memory of 2 GB climbs up in one second

second time: each time different, sometimes 10-15 fps sometimes 5-8fps 2GB climbs up fast

third time: 15+ fps 2GB climbs up slow 10+ seconds

fourth time: 15+ fps 2 GB climbs up slow 10+ seconds

what I expect:

always 15+fps or at least fourth time 1-3fps

PS: I have a clip where I generate the provided F3+L-files. The files are generated while the game is slow, including the F3-screen, however, I cannot upload this as it is to big. How is that usually uploaded? The second file is meant to be exactly 2 minutes after the first probably didn't work because of lag.