What happened ?

I had like 564 hrs at POE 2 till day one and I gave some break waiting for new patches and content .Then 2 days ago I decided to log in and play the game again .
Well I do not know where to start :(the game was regularly patched in my steam library)

first I tried to log in and saw a mssg saying undr maintanance well cursed my luck adn searched for info and there was none .so tried to log in again and after like 15-20 clicks I logged in .
Opened a new char at this hunt season and started to play and whehn I was entering the very first village from starter area the loading screen was there for 2 mins and then my char showed but was not moving and then after like 30 secs it dropped to login screen again .
So this freezing thing happened random while lvlving sometimes 4-5 times ina row.

I googled it and the most used solution was unchecking multitread box which really solved the problem but dropped my fps from 144 to 35 .

WTF seriously I played this game 500+ hoursd without an issue and now it is a mess .Do I ve to frekin uncheck the multitread box every time I try to TP ?
What the heck is this all about ? WHY DO YOU EVEN HAVE A BOX TO MAKE YOUR CPU WORK ONA SINGLE TREAD ? (which clearly you wrote that you do not advice it)

I want a proper solution for this problem pls .The game is literally unplayable for me now.