Can I get a 3999 elo in ches then win another chess and reach about 4000 elo or not?

I think it's possible

Don't bother. This is why.
https://lichess.org/forum/general-chess-discussion/is-there-a-maximum-rating#NcM6pct4

@JYLee115 said ^

I think it's possible

I think it's possible if you gain enough rating points from the win ;p

good luck buddy.

"Can I"

• No, you cannot.

Glicko-2 has a "sanity check" where if you hit 4000 you get reset to 1500, I believe.

We believe in you Bro !