Freeze/lag when I watch someone

[LarSokLi]

Hello,
When I join a game of bedwars after like 10-15 min in the same game my game start lagging every time I watch someone, this thing happen also in skyblock and others game and in others servers
I have this problem since a long time and I dont know how to solve it I try many things like giving more RAM to minecraft or trying other dns but nothing work
Someone have an idea ?
(sorry for bad english im french)