Please explain USDC – LINK, AAVE, CRV, WPOL and back to USDC movements.

About a week ago was contacted by a dude, who promised to teach how to trade crypto and make money blahblah and offered this directory:

To trade USDC that I invested, not so much money, to trade into 4 coins: AAVE or CRV or WPOL in the specific times of the day and then back to USDC. Polygon network.

I learned how to do it connecting different platforms like uniswap or sushi, all good. Made 30% from invested money in a week.

At last, the dude said the training is over and he wants to put me on rotation and charge me 20% of weekly profit if I invest 1000 USD now, which I’m not ready to do now, after that he didn’t want to proceed with me.

Can somebody please explain what’s the catch and whether I can continue doing these trades on my own? Can I make some money if the sum is rather small – less than 100 USD

Would appreciate your honest opinions on that and your help!

Thanks.