I dont know where i can get better eq on my level .

My build is from here :

https://mobalytics.gg/diablo-4/builds/sorcerer/fireball-illuminator

I have this wand but without Ga so its worth to upgrade ?

Also will need Helmet but i cant kill Uber bosses with these Staff

How increase my damage ?

I have too low damage for pits level 50 to unlock torment .

Should i upgrade paragon board or something Like this ?

Im using this build now, you should be using the starter version.... the gloves are the most important piece of this build. paragons and upgrading your glyphs are really important here. i would not upgrade the staff until you have a GA one yes and lots of mats. If you have boss mats i'd join a rota party for boss most are spirit born and can one shot the bosses.

d4 varshan boss i can kill him but can get uniq with ga ?

this build can do t4 with no GA worry about getting the uniques you need first then go to t4 as soon as possible..