The answer is, it's a function of time exposed to benzos, and the doses involved.
I used benzos at massive doses for years, and went through two full on withdrawal syndromes. The benzo addictions were punctuated by around 6 years of non-use. After my second instance of full on benzo withdrawal, somewhere around 2012, I never really felt like I fully recovered. Maybe 96%, but I never felt the same, with permanently higher anxiety levels. It's as if the withdrawal didn't completely end.
Even a decade later, in say 2022, a single good sized dose of etizolam of alprazolam was followed by a 4-5 day period of rebound anxiety and insomnia. I remember in 2018 I used strong doses of etizolam daily (maybe 5-10mg per day) for 5 days. The rebound was so severe that I was a shell of myself. My girlfriend would be normal TV shows we would watch, like the Sopranos or etc, and I was so anxious that I could only cartoons like King of the Hill because anything slightly disturbing would freak me out. Severe anxiety, insomnia, I stopped talking etc (I'm usually very jovial and talkative). Horrifying dreams resembling horror films. I had a dream some entity was flying after me in a dark house and I woke myself up because I was yelling "help! help!" over and over again.
I abused benzos at high doses doses for years, which causes epigenetic changes to GABA-A receptors. Essentially, when GABA-A receptors are exposed to long-term and high doses of benzodiazepines, the body tries to balance things out by decreasing the sensitivity of GABA-A receptors. When this happens in the long-term, the epigenetic changes are so profound that they can become permanent, resulting in permanently less sensitive GABA-A receptors.
Benzodiazepines are actually more likely to induce epigenetic changes than alcohol because of the extreme specificity that benzodiazepines have for the GABA-A receptor, binding with high potency on a specific little pocket of the GABA-A complex (between the alpha and gamma subunits). Overuse leads to not only short-term receptor downregulation and altered subunit composition, but long-term damage (via increased DNA methylation, which can suppress the expression of the GABA-A subunits to which benzodiazepines -- and other things -- bind, and histone modifications, which basically causes the DNA to become more tightly packed and less accessible for transcription).
In more basic terms, they fuck up your GABA-A receptors, reducing their function. If you push it hard enough, like i did, you will cause potentially irreversible damage. This essentially leaves you in a perpetual state of mild benzo withdrawal, like me.
Maybe in the future there will be some gene therapy to help repair this.
Morale of the story, the more you fuck with benzos, they more they fuck with you. They are neurotoxic when used for prolonged periods of time. But they are life saver when used very occasionally. But if you use the life saver too many times, you start to pay an increasingly heavy price.