These can be potentially life-threatening / self-harm inducing. Ironically, the logical solution is fairly simple, although it may understandably raise some initial concerns.

It has often been said that "alcohol is the cause of and solution to all of life's problems" and never more literally than in this instance.

This observation has been shared by various well-known people with ME/CFS and related online groups such as https://www.reddit.com/r/hangovereffect/.

Although this author's opinion is bound to attract some criticism, I'd also advocate that using exogenous alcohol, as an over-the-counter tapering schedule against withdrawal from the microbial-sourced alcohol (and the 2 downstream endogenous psychoactive substances) is a far simpler and less problematic therapeutic intervention than administering exogenous opioids and/or benzodiazepines, in an attempt to create an effective tapering schedule.

These 2 classes of drugs are both well-known to be "drugs of dependence" and will likely require high doses to be effective symptomatically. High doses of these interventions can create a long tapering schedule of their own that may last 6 months to a year and is known to be highly unpleasant.

Following a strict alcohol tapering schedule and avoiding dosing at levels which induce alcoholic intoxication is required. The goal is to remain in a tolerable level of withdrawal symptoms during the taper, rather than attempting to make the process "feel pleasurable". This will be highly personalised and likely involve multiple doses over the day / night, which decrease over time. Having appropriate monitoring and management would be highly advisable.

Caveats and Risks
1) It would be optimal to avoid alcohol reaching the gut microbiome. Neat alcohol such as gin, vodka or whiskey, when taken in small sips and absorbed largely via the mucous membranes found in the mouth, throat and oesophagus would be a preferred route of administration.

2) While alcohol add-back therapy is known to be problematic in chronic alcohol use withdrawal due to the risk of behavioral disorders, such issues are less likely to arise in conditions like ME/CFS or Long COVID where alcohol consumption was not voluntary or habitual. However, professional oversight and adequate peer support is still recommended to manage the process effectively and provide a safety-net.
 
In addition to alcohol tapering, certain supplements may also help manage withdrawal symptoms relating to hypometabolism.
These include:
Coffee or caffeine.
Forskolin (will need tapering).
Hesperidin.