IMHO it's alt season and I have a lot of projects that are performing better than Bitcoin. But eventually most altcoin projects will die. Therefore I agree with your idea to invest in altcoins and then when the price has reached the target we want to sell and save in BItcoin. I've done it on several projects like rndr and worldcoin. I once bought RNDR at $3 and sold it at $8 and then bought Bitcoin. I never regretted even once RNDR hit $12 because $8 was my price target.
We should not think about pumping coins but if we buy some top altcoins then there will be no worries about its declining price. Your idea is very beneficial and if every individual accepts such an idea then every individual will be in benefit. Actually Bitcoin is not as risky as that is altcoins so take benefit from altcoins immediately and invest it in Bitcoin so you will realize how profitable your idea is.
Another better step is to not hold your coin once your target is achieved so you take every step wisely therefore you are feeling satisfied. In case of investment if someone uses his mind and gets help from his earned knowledge then chances of losing money will be minimum.