Do not stress yourself by looking for any other cryptocurrency. Just go straight and invest in Bitcoin if you think that you should choose another cryptocurrency to invest that money. If not then continue to hold that BNB it is already a good choice. Don't make the mistake of investing your money in the wrong cryptocurrency and ending up losing it.
The OP have many option with altcoin to buy and looks little stress because worry which one are potential coins to buy, actually I like with your ideas as BNB potential coin and focus there only. Without increase almost 100% profit every time but keep consistent value with BNB coin and always have chance recovery when price drop, not sure with other coins how faster recovery suddenly have drop value. Could be faster than BNB without one days or one week can wake up and reach higher price again.