BTC, ETH and XRP seem to be enough, too many coin choices will indeed be confusing. But let's look at the potential of each top altcoin, it will provide double profits if in the bull run season all altcoins rise. You just need to choose which one is the best and use it as your main investment. Be wise in choosing altcoins and make sure you don't put all your eggs in one basket, there are many baskets to choose from to maximize long-term investment.
XRP is definitely not the one I would have picked there. I have always said that four horseman of crypto is btc, eth, bnb and ltc because those are the four that is known the most and loved the most with as little questions as possible.
I know that it is going to be a tough thing for a lot of people to accept that but XRP has been a scam ever since it started, I do not think that it would be something that could make a profit that easily and we should avoid it as much as we possibly could. I know that it is not going to be a simple thing, but I can't really make it work that easily neither, it just doesn't seem to be possible for people to understand why they should stay away from XRP, so I just let them be and learn themselves.
You've clearly done your research, so I value your opinion on the "four horsemen" of crypto. Bitcoin, Ethereum, Bitcoin Cash, and Litecoin all have a strong reputation. Heres a different way of looking at XRP, though. I get your concerns, but I think calling it a "scam" might be too heavy-handed. Of course there have been problems, and I understand some of your worries. For the sake of argument, though, lets say that every asset type has its own problems and critics. Remembering that is very important. Although I have my doubts about some cryptocurrencies, I believe in doing a lot of study before making a choice. As an alternative to completely ignoring XRP, I believe it should be constantly observed and evaluated. Crypto is changing very quickly, and I've learned that I should never completely rule something out.