Never put all your eggs into the same basket, or into very few baskets. However "over diversifying" and buying into too many questionable quality lover market cap alts or tokens also not a good idea, as those used to drop more steeply on a bear market, so you can accumulate some really ugly losses. Probably BTC and 5-10 higher market cap established alts is the most balanced choice. Maybe it also worth to go for some coins/tokens what can generate some passive income. If you are the adventurous type you can gamble with 10-15% of your funds in high risk - high gain things.