I have a Singleplayer World where I just build some stuff and enjoy the beauty of the game but when I moved to 1.16.100.58, joining my own world takes so long and chunkloading takes so long as well, also when a mob enters that chunk that hasn't loaded yet, they appear frozen and doesn't move at all this is also one of the reason why I died many times, I saw a Creeper at the unloaded chunk because I'm waiting for the chunk to load so I went to the Creeper and tried to kill it but I saw it didn't move so I just stand right beside it and spamming it but then the chunk loads then it blew up instantly and killed me... The loading issue is one that I hate the most because sometimes I save and quit at a sticky situations then when I think of a solution to escape that situation I'll get back in the world but because it takes so long I just end up with a death screen this loading issue takes even longer when you have a resource pack or an addon to that world... There's also another bug with almost all Beta, I'm using Cherry Mobile Flare S6 and in every beta I can't open Minecraft, I just get stuck at the loading screen, for me to fix this is I need to make a new user at my phone and install Minecraft at that other user then I'll be able to open it but I understand why this are happening and I hope you're going to fix it... I love your game! I've been playing it for 6 years now and I never get tired of it... 

I've had a thought that maybe the Chunkloading itself is the main problem because I think that the reason that I'm getting stuck when entering the world is because the chunk is loading so slow that it's struggling to put in because it can't read any blocks around me because the chunk is gone... This also kind of make sense because when I get in there's only a few chunks loaded... 

I've showed some other bugs that I know on the video that's not included to the description... If you see on the first video, I went to the users and clicked the add guest, that's what I said that I do everytime the game doesn't open... There's a sound delay at the game itself too but the video doesn't have an audio... 

Video 1:

https://youtu.be/QhZDl8nLpsU

Video 2:

https://youtu.be/uGqQ-V3-0ZQ