I dont really feel like leveling another character and I just want to do the 40 achievements as easy and fast as possible
Any recommendations lets say 20 ex budget

Nothing is op for ranger at 20 ex. Even at 200 ex. You're still not "op"

semantics.... must be fun at parties. What I mean is can complete all content on a 20 ex budget

20ex you easily just buy the hard achievements.

Toxic rain can do almost everything.

You could go with your ranger and go for Lightning Arrow. Got my 40/40 easily this way. Especially the blood crucible challenge needs a lot of speedy map clear. Else you could look for a Magic Find Ranger Build, they start from cheap and can make u rich while getting ur challenges done, so u could also pay for some services instead of doing them by yourself.
Cheers

more like 10-20 mirror is close to op.

Toxic Rain - Ice Shot - Tornado Shot. Do whatever you feel like mate