Why bot both. Buy Alts that paired it Bitcoin, so when you're take profit from Alts you will gain Bitcoin. HODL it until it reach $100k.
Both altcoin and bitcoin is good to invest or to buy for, but i think bitcoin can give me more money in the future, rather than altcoin, and i know to myself that investing or choosung bitcoin is the best decision i will ever made, by choosing bitcoin i should know how to hold or to wait for long time so i can earn more money.