If you lost 50% in the crash and gain 50% afterwards, you are still in a 25% loss

If you have $1000 invested in Crypto and it crashes -50%, you will be left with $500 worth of your coin ($1000 * 0.5 = $500)
If your coins now starts pumping and you gain +50% after the dip, you will have $750 worth of your coin ($500 * 1.5 = $750).
So you'd be still in a -25% loss.

If your coins drops 99.99% - 100% from your $1000 investment and it gains 100%, your portfolio will have $0 - $2 value.

In order to get back your investment for a -50% drop, you will need a +100% pump.
After a -60% drop you need a +150% pump.
If your coin drops -95% you need +1900% to break even.