Did this advice work for the OP? I mean, even if he doesn't have money to invest in bitcoin, his bitcoin investment is minimal and insignificant. Instead of diversifying each asset with just a few tens of dollars, the OP should focus entirely on bitcoin. The advice is correct, but we need to give the correct advice for each person's situation.
I also said that Bitcoin is the main investment, Diversification is only optional and may be chosen when you have enough money (maybe hundreds of dollars).
Given that OP's financial situation can only afford tens of dollars, DCA can be applied every time OP earns money.
Although the entire crypto industry depends on Bitcoin, I will personally divide my investment into several altcoins that are indeed quite good developments such as ETH which is my favorite altcoin.
And I don't think investing in altcoins is called diversification. Because the entire crypto industry depends on bitcoin, if bitcoin crashes then all altcoins will disappear. Therefore, it cannot be called diversification. Should only diversify non-crypto-related assets.
Diversification methods can be related to any investment including crypto, it's just a matter of choosing.
If not crypto-related then other investments can be centered on Gold, Real Estate, and maybe a piece of land.
That is already included in the broader investment.