Where should i invest?

It is risky no matter what coin you invest, if you want good profit in quick time.
To earn good profit in short time, you need good knowledge and experience in trading.
Or just stick to the basic "buy low, sell high" rule.

There is a chance that new and cheap coin's price will goes up 100x 200x times in short time. But nobody really know which coin has that potential.
It is the only way to get rich in short time.

BTC, ETH are reliable cryptos but you are slightly late to the party, so you won't get rich in short time just by investing in them.
If you are aiming for a long term, they are good investments IMO.