I suggest not to join such premium signal because it may be scam or you will not get signals at the right time . Why do you pay for it, do not take such risk. This forum is really helpful for newbie to learn more. Do your own research. If you experience u will get to know.
It is not mandatory to check the every single telegram group and join them. The more the trader fails, the more experience is gained through the failures. I don't advise joining the premium signal groups, the real traders never share their trading setups for few bucks. As you mentioned checking the recommended altcoins on the online platforms and investing these altcoins have better ROI.