From your post there are many red flags or factors which points to a scam project. First you said the project was created since 2018 and since then there have been no progress till date, in my own opinion this shows a team which aren't serious at all, 2018 till date is a long time to at least bring something good to the community. Also, for a project getting such amount of money and yet can't follow the roadmap is another turnoff, okay let's assume there was a shift in the roadmap what happened to the funds generated? Why aren't there any progress? It also shows that, either they lied about the funds generated or it is no where to be found. Lastly with the huge reduction in the telegram group points to a platform which users have lost interest in; to me, the difference is too much.
Furthermore, in my own understanding, you can ask questions in the group to know more but to be frank the project doesn't look legit with this type of actions.