Hi,
My opinion is that the block should be lifted. However, to the best of my knowledge, an appeal of a local block to the larger Wikiverse has never been successful. I am guessing that there are at least four factors here: 1. a lack of consensus for a process for appealing a local block to the larger community, or whether such a process is desirable, 2. a lack of skilled community human resources capacity to review such appeals (I would guess that reviewers of appeals would get flooded with hundreds of low-value appeals, that the job would be emotionally and intellectually difficult, and that the queue for reviews would be many months long), 3. a lack of confidence among people who are not proficient in a language to review a dispute that happened in that language, and 4. a lack of volunteer capacity and financial resources for highly accurate translations of appeals and their related content.
Asking WMF to overturn a community block sets a precedent for them to substitute their judgement for the community's. There is a history of problems with WMF clashing with the community, and I have an ongoing objection to WMF's unilateral and opaque uses of global blocks. I would not want WMF to forcibly intervene in matters like this. Instead, What I recommend is diplomacy. The admin who made the block appears to have intermediate proficiency in English. I recommend first having a diplomatic discussion with that admin regarding the block. The admin could be persuaded to remove it. By "diplomatic discussion" I do not mean telling the admin bluntly that "you are wrong and I am right". An assumption of good faith, persuasion, and respect are likely to be valuable here. Try diplomacy first.
If the admin remains unpersuaded to unblock the user then, to the best of my knowledge, the only routes of appeal available are on that wiki. I am unfamiliar with the specific situation in Armenian Wikipedia, but I suggest looking for a local policy for appealing blocks and looking for a username policy. Intermediate proficiency in Armenian is likely to be highly desirable, and likely necessary, for productive conversations on that wiki regarding a block appeal and/or proposing a change in local username policy.
I realize that the concept of appealing a local block to the global community sounds like it is worth considering, but even if in principle there becomes a consensus that we should allow this, implementing such an option for appeals would likely be difficult and time consuming in practice, and without highly accurate translations which we do not appear to have sufficient volunteer or financial resources to support at this time, I think that the potential for mistakes due to misunderstandings is high.