If ICO is under radar and doesn't get much attention it may not be a good investment afterall. I personally don't consider ICOs with less than 10k telegram followers.
An ICO with lots of telegram followers doesn't mean anything. Nowadays, all project use airdrops to create hype and to get people to join the telegram.
Telegram followers numbers can be manipulated. Better to look at the fundamentals, like the team, the product use case and the tokenomics.