Classic. When Bitcoin has an up day, “I’ll buy in the dip.” When it dips:
(little scary pullback tbh)
You have not said anything about your risk tolerance. (Among other things.) There is no one-size-fits-all formula to apply to the numbers that you stated.
And I am probably the wrong person to ask: I bought into Bitcoin for political reasons, without regard to the market. It has worked out well for me; but I did not plan it that way!