Actually, it is mentioned. See image: https://ibb.co/ncdghzc

That is one more argument to make me doubtful. If the official web support page mention this Telegram link, then one more reason to believe it should be legitimate.   Oh! furthermore, I now remember that the suspicious guy who ask to enter my the details about my wallet, his name was listed on the right panel on the Telegram app. where, supposedly all officials of the myNode channel support team have their name listed. That is really weird.

I haven't conducted my second attempt yet. But I will post the results here when done.

As for the other problem with BTC_RPC_Explorer, well, no it is not solved yet. I'm working on it, but I'm getting out of ideas at this point. I've tried all you guys suggestions with no success so far. The main issue seems to be that upon restart of the RPC, the edited .env file gets rewritten back to original. I will keep adding to the question with more details.