Please NOTE that I am not a doctor, or a medical professional of any kind and I'm not giving medical advice—the following is my experience and what I found helpful as I was not able to find a medical professional to help me discontinue Effexor/venlafaxine and manage/minimize the withdrawal effects. When it comes to getting off Effexor, each of us is our own guinea pig—Effexor is a very powerful antidepressant that affects the brain's neurotransmitters (serotonin and norepinephrine) and it takes your brain a while to figure out how to rebalance serotonin and norepinephrine while reducing, or after quitting Effexor.

When I started experiencing withdrawal effects back in the summer of 2018 after slowly tapering completely off Effexor, I was prescribed Valium short-term by a Care Now (walk-in health clinic) doctor when my akathisia and anxiety became overwhelming. She had me take 5mg Valium twice a day for three days straight (I stayed home from work) to "get ahead of the anxiety." Her "get ahead of it" strategy was pretty effective and she prescribed a small number of tablets to use as needed if the anxiety seemed to be building again.

I did not want to rely on Valium—I would be exchanging taking Effexor to taking a very addictive drug. I read ALL of the "Tips on minimising withdrawal symptoms from Effexor (aka Venlafaxine) discussion thread on this site to learn what others in my situation were experiencing and what was helping them and did a lot of online research re getting off drugs.
P.S. The "Tips ..." thread is now over 600 pages and it is WORTH reading every bit of it.
P.P.S. The post above by njoys has links to many helpful sites.

Through trial-and-error and research, I came up with a number of OTC medications and supplements that helped me. At first, I took these supplements five times a day; today, I am down to once per day. The most helpful are l-tryptophan (DO NOT take if you are still on Effexor) and GABA. Ben*dryl, Bon*ine, or other seasickness remedies can reduce/minimize the dizziness/vertigo and were very helpful in the beginning; I seldom need these today.

What I take daily to minimize the effects of Effexor discontinuation—
2 500 mg krill oil softgels (if you get brain zaps, fish oil may be more helpful)
2 1,000 mg Vitamin C (helps the l-tryptophan) softgels
1 500 mg l-tryptophan capsule (Lidtke brand)
1 500 mg GABA capsule (Solgar brand)
1 500 mg l-arginine capsule
1 470 mg ashwagandha root extract capsule
1 5,000 mcg Vitamin B12 (methylcobalamin) chewable tablet
Occasionally—half of 5 mg diazepam (prescription aka Valium) tablet (a few times per year)

Based on how I feel these days, I could taper off the daily dose of supplements. I have been procrastinating about doing this as as the capsule supplements don't come in smaller doses and as we know from tapering Effexor, cutting into a capsule and making smaller doses is a messy and time-consuming process. I may, instead, try waiting longer between doses—rather than taking the supplements daily, perhaps take them every day and a half; then, after a few weeks, go to every other day, etc.

Hope this helps!