I got into the bitcoin again last year after losing all my 4.5 bitcoins to ponzi schemes early last year. I bought in bitcoin again at $20k. Now bitcoin is $6k+. I'm regretting my actions.

For me you can still come up with the money you lose, it is normal that a lot of people is making some mistakes here in crypto world but the important thing we really need is to learn from our mistakes to get more better and to make a good decision next time.
Indeed, we can recover our losses by trade that bitcoin with other prospect altcoin. Most altcoin price drop againts bitcoin and i think if want to recover that loss, i think trade it if having trading knowledge
As for me if I have bought higher price and the current is too much lower then one best way to have better output is to hold and wait another rise to be equally or close to our buying price to avoid to much loses or maybe we can do trading buy shifting our holding to the promising altcoin and gain little by little profit until the ROI was meet.