I have followed some guides but I wonder whether I should try and commit the time to learn to trade manually without the use of Bots? It's just a nice idea to have passive income while I am at work and asleep.
That's the answer to your questions. Instead of joining these so called signal groups you can learn to trade by yourself.
2% a month is a really low return IMHO. You can easily make more than that if you learn how to trade.
After you are good at it may be you can yourself develop a bot or hire someone to create a bot for you or purchase a bot and then modify it as per your strategies.
This way you will learn how to trade and also earn passive income when your bot starts making money for you.