What amount do you classify as much capital. To start your investment you dont need an actual amount to start it, all you need is a stable job, an income, and a discretionary income from your actual income. With time you can have more passive income to increase the percentage of your discretionary income you do invest with, that is if you are using the dca strategy. However, most rich people prefer to lump sum, since they do not want to hesitate in having a good amount in their portfolio
You don't need a stable job to invest. You need a source of discretionary income to invest. There are many people whose source of income is not stable. You need to find discretionary income from your source of income.
There are many people who invest but they don't have a stable source of income. For example, when a contractor takes a job, you don't get paid until the work is completed. There are many types of jobs where you don't get paid until the work is completed. If they want, they can find discretionary income and invest through proper financial management.
If I talk directly about investing in Bitcoin, then I will say that if someone creates an emergency fund and a reserve fund for long-term investment and does not invest the total investment amount at once, but buys Bitcoin in equal amounts at regular intervals, i.e. follows the DCA method, then this will be the safest investment strategy because it reduces risk, and helps the investor to remain stable due to market fluctuations or volatility, basically this is a simple strategy to reduce risk for long-term investors. Finally, one thing to always keep in mind is that it is better to invest aggressively from prudent income than to invest the necessary money like gambling.
What did you mean by Investing the total investment amount at once? Anyone amount or money that is within your discretionary, even if you invest it at once there's nothing wrong the only time something will be wrong is if you used all your discretionary and went to touch money that is meant for other things, it means you are really joking with your investment especially when you don't have something that can cover up what you collected immediately. You can invest as you like, as long as it is within your discretionary but as a no coiner or low coiner you should have limitations.