Chunks/blocks are slow to load, even with no resource pack

So, I want to play on servers because I'm bored. While entering a server(it's nethergames), and I'm gonna play bedwars, blocks are slow to load causing me to lag, even my signal is strong and server's signal is strong.

 

Steps to produce/reproduce

 

1. Pick a server(nethergames might work since the bug occurred there)
2. Enter bedwars
3. Pick squads.

 

What I expected to happen:

Blocks will load quickly

 

What really happened:

Blocks/chunks are slow to load causing me to lag

 

Side note: I boosted my RAM memory. But still this happened