All top 10 coins are smart long term investment. Situation and last years proved that again. When price drop then buy more and accumulate in your bags more. No need to invest much. But offcourse dont invest your last penny in crypto. Risk is big , no free money anywhere.
Top 10 in crypto world changes though, it is not always the same. I am not sure if BNB was in top 10 before this year, but it was always a "good" one and that's it, this year it became third biggest coin thanks to help from BSC becoming a huge deal. At the same time we used to have BCH and BSV in top ten and now we do not have those things, we used to have dogecoin way way way down the ranking list and it peaked as much as fourth biggest coin at one point and still in top 10.
I understand that top 10 gives people comfort but always pick the smart things in that top 10, make it top 20 if you want to make sure, and do not invest into coins that looks a bit shady and people talk bad about, nobody can argue that btc, eth, bnb would be bad, those are good, rest of the order has to be checked by you and after your detailed research you can find the real good ones that will not go down quickly.