1. Is it okay to rotate my profit into another coin, or should I invest it in a stable coin or leave it in USDC?
2. Do you think investing in 20 coins is too much? Should I reduce my portfolio?
1. Both are good choice but you don't invest in a stable coin. It's a way to retain the value of your profit.
2. That's too many and too much diversification. I wouldn't do that to be honest because that's almost going to get you nothing. You might earn with one pump from your 2-3 coins but then get a terrible loss from the other remaining coins. So, don't diversify a lot and get at least 2-5 coins of your choice, the ones that you have the strongest conviction of holding because you're going nowhere with that number of cryptos.
Lot of people think that holding too much altcoin would increased their chances of making profits from them because they thought there is likelihood of them soaring above expected but have also forgotten that those altcoin can as well increase their chances of losing them all entirely. Like you said having bitcoin as most priority coin and then includes few altcoin maybe 3 of them likely better, just as holding Ripple, BNB and Ethereum maybe he may decides to includes Tron and Sol on their portfolios these coin is enough to hold than going to hold series of coin that could easily create dying part for him.
You cant be able to ignore the probability or chances knowing that this market is really that unpredictable then everything or anything could happen without expecting or anticipating it, which this is the main reason on why there are those people who would really be that wanting or trying out to accumulate as much as they could when it comes into their altcoin holdings on which we cant blame them out.
The primary thing that comes up into our mind that Bitcoin investment would be hardly give out 2x with our investment on which it will really be that totally different when investing into altcoin specially on meme coins or some low cap coins in the market. If you do able to accept the risks involved on investing with those altcoins you choose then it will really be that entirely depends on you. There are times that we cant be able to resist because we do mainly think up on becoming rich with our investment when the bull run time comes. So it will really be that up to you on how you gonna handle your investment.
If you do find out that it needs to be rotated then its your choice. Diversification will really be the most common way for you to reduce risks on getting that totally wrecked with your investment since there's other coins that will really be able to pull up if ever you do have some loses in other coins. Try out to maximize out things accordingly and you are the ones will really be making out such decision