I haven’t taken Effexor but I have gone on and off Lexapro several times. The withdrawal is real and supposed to be even worse for Effexor. Unfortunately there’s not great evidence that lengthening the taper really prevents all withdrawal symptoms. That is because these medications don’t affect the brain in a linear way - the biggest drop is when you go all the way to zero, even if you have been on a very low dose.
One thing I’ve seen recommended though is switching short term to a longer-acting SSRI like Prozac. Supposedly that can make the withdrawal smoother:
https://www.health.harvard.edu/diseases-and-conditions/going-off-antidepressants#:~:text=Many%20of%20the%20symptoms%20of,)%20for%20shorter%2Dacting%20medications.
Another thing you can try is reducing the dosage now to see if you can reduce side effects and still have some benefits. I went down to 5 mg Lexapro from the lowest officially recommended dosage of 10 mgs. That reduced almost all of the side effects I didn’t like and still had benefits.