Bitcoin should be bought and held regularly based on how much more profit it will make in the long run.
In 2016, 1 Bitcoin could be bought for $400, now it costs $112K+ to buy a Bitcoin. In the last 10 years, the price of Bitcoin has increased by hundreds of times. Now it is not possible to buy a whole Bitcoin with less money than before. But if we calculate the valuation of Bitcoin in the future, then if someone follows DCA for 4 to 10 years with less money and cannot buy the whole 1 Bitcoin, there is no problem. Because after 10 years, the value of every Satoshi he has will be several times higher. So even if he cannot buy a whole Bitcoin or a whole Bitcoin, there is no problem because after a long time, the profit will be many times higher than the investment.
None of us can ever see or say the future. So no one knows what the price of Bitcoin will be in the future. So instead of investing on leverage, first set a goal of how many Bitcoins you are willing to deposit in your portfolio. If you invest like that, you might get something good. As you said, if you invest on leverage, if you hold on to $300 and expect to get 50,000 from it 10 years from now, if you do and the price of Bitcoin does not increase as expected, then you may be disappointed and your faith in Bitcoin may be lost.
So first you need to set a goal of how many or how much money you will save in Bitcoin in your portfolio. If you go ahead like that, it will be much better for you.
Setting goals to determine or know how much Bitcoin to hold for a given period of time doesn't really matter, what matters is how consistent and serious you are towards actualizing that goal. Some people set goal and don't get it because they are not working towards it and they are not consistent and one thing you should know is that Bitcoin is not something you can just do, you need to be patient and make sure to use the necessary things that are involve such as your discretionary income and accumulating consistently. And lastly you don't deposit Bitcoin in your portfolio rather you accumulate it.