Perhaps, the idea of buying Bitcoin only is not a great idea for me. Altcoins are also profitable and sometimes even more profitable than Bitcoin. But, it doesn't mean we have to invest in any altcoin without any thorough research otherwise we just fall into scam coins that are already flooded in the market.
What I can say OP is that making a choice of investing that you know was profitable and most of all it has a working product as it gives some ROI assurance.
Honestly, I consider those coins that are on the top 10 to be a greater choice but I haven't chosen them all, why? I'd rather choice 3-5 coins in bulk than buying number of different coins.
Given what's happening in the market, I will prioritize bitcoin, and I won't DCA with altcoins. But I will agree with you if just investing in bitcoin is boring, and I also like altcoins.
Regarding investing in altcoins, I have the opposite opinion of you. First: I don't invest in altcoins during bear season, Second: I don't invest in top 10 altcoins like you, I will only invest in altcoins when bitcoin shows signs of bottoming and begins to accumulate. I will be looking at altcoins emerging in the market, which have the potential to replace the top coins in the next bull season.
Maybe you had a trauma about what happened with Luna, FTT and other altcoins. And that is why you are skipping them but that was only for now right? Maybe there was still a chance for your heart to get warm on them.
But for now, it's okay if the coin that you will invest is BTC. I too like it to be honest because BTC was still the controller of the market and once the demand is shifted again in BTC, then there is a big chance that we will see the bull run in a much earlier time than on what is its designated time which are 2 to 3 years from now. If you think investing in BTC alone is boring then there are still other assets that you can add, not just altcoins or cryptos but we also have stocks, bonds, real estate and many more.