I think the most secure trading is to use some money from trading capital and use money that will not be in use for the near future,
for example I have $ 1000 and I need to use the money for my family's living needs, then I can use $ 250 for trading and the rest to survive, do you mean from this revelation?
this method is used so that you are not too depressed if the money you have stuck in the expensive price.
this is the basic method to trade crypto. let's say you have 100% capital and want to buy a crypto you should spend 10% of it to buy at the buy point that your decide, when the price go down below your first target point use 20% of the rest of your capital yo buy again but make sure you buy at the dip. and if go below again use 50% of your capital, and when the 50% is up it will cover the loss of 20% and 10% .