Buying Bitcoin without having an emergency fund was the biggest mistake you made while starting your journey many years ago, because if eventually you were able to buy with some spare funds that wasn't urgent, you probably wouldn't have sold all and had a few as  Bitcoin appreciated around 2020/2021. But however, I'm happy you learnt from your previous mistake and now holds Bitcoin with an amount you can always afford to lose. So back to the question you just asked above regarding what percentage is best to diversify as a Bitcoin investor. And for me, I will say 80% in Bitcoin is best while our cash should be 20%, because investment is always meant to be higher than expenditure.

Yes Bitcoin is a long-term investment, so it is important to create an emergency fund to manage long-term investments consistently and that means that only if there is a financial obstacle during the investment, the emergency fund can be resolved. The investment can be managed with discipline so that if there is a financial problem, the investment does not have to be completely closed or sold. That is why it is very important to create an emergency fund. Another thing is that the price of Bitcoin is volatile. Another thing is that the future is completely unknown, so we do not really know when the emergency fund will be needed, so it is very important for us to always be careful and be prepared. If we cannot manage our investments consistently and hold Bitcoin for a long time, we will never be able to reach our goals or make long-term profits from Bitcoin. As a result, we will face financial losses.

Any money that will be issued as emergency funds should be readily available and easily accessible. This is because you don't need to pass through protocols to access your emergency funds. Emergency funds should be saved in your local fiat and kept in an easy going account or kept in cash. Emergencies may occur anytime and if you don't have a good support to help you, you can end up selling off your main bitcoin stash.

Leaving your emergency funds as bitcoin can expose a person to losses and this is because emergency may occur at downtime and you will not have anywhere to run to order to selling at loss. This means that even if the amount saved for emergency situation in bitcoin was supposed to be enough for such emergency, you may sell at loss and the said bitcoin will not be able to solve the same problem when it happens. Save your emergency funds in your local fiat and invest in bitcoin for a long-term.

If you do not create a backup fund for investing in Bitcoin, then if any emergency problem you face in the long run, you may have to sell your Bitcoin holding. But I would not say that keeping 80% Bitcoin and 20% as cash is fixed for everyone. Not everyone financial situation, responsibilities and expenses are the same. If a person uses 80% of his discretionary income to buy Bitcoin, it means that he is investing aggressively. If that person has a strong cash flow and there is no instability in his lifestyle, and his expenses are fixed every month, that person can do DCA in such an aggressive way. But if a person has more responsibilities and unexpected expenses are irregular, 80% of his discretionary income may not seem reasonable. At that time, that person will do DCA based on his situation. Even his DCA amount may change every month or week due to irregular income and expenses. It will depend on his cash flow and expenses.

You said it yourself "you learnt the hard way loosing alot cause of wrong order of your investment.

I would say 100% savings in bitcoin without a backup would only make one sell at a loss when there's an emergency fund needed. When thoughts or things like this comes to mind or happens. It's always advisable to do the needful of saving emergency fund elsewhere different from your bitcoin savings. Doing this will save one from being at the loosing end when emergency funds is needed