Exactly.Invest only in top 10 coins because these will eventually give you huge profits particularly when bull run comes.And having ETH and BTC are really good choices because these two are considered the most potential coins in the market.Keep on studying the crypto market so you will gain more valuable ideas which will mold you to be a good trader in time.
In fact it is the other way around, it is true that the profits you can get out of the top 10 coins are very good but those are the safest coins to invest in the market, if what you are really after are huge profits then you need to take a risk and invest in coins outside the top 50 or even the top 100, your risk will grow exponentially with such coins but at the same time the rewards grow as well and depending on your objectives that could be a good thing or a bad thing.
Read about them. These two are splendid coins with enormous profits ratios. Although in these days al the coins are giving bad numbers but still people are earning fantastic from these two supreme coins. ETH is too cheap and it suits to every pocket but bitcoin, yeah it is a bit fluffy.
But, when you get maximum know how about them, try to map them to your needs. Perhaps, one is better for me, wouldnt be better for you so decide yourself.