1, you don't have to sell it as a loss
2. 50% of the position would probably be smarter if you were itching to do so
3. Nearly every decent crypto (and bitcoin is #1) comes back... (miners will too)
I've learned, the hard way. Now I leave positions, when I can leave a free position behind. I'm guessing you could leave with your investment soon enough.
The ships here will rise with the tide, if you need mstr exposure, maybe get a few with fresh powder on a down day.
I've been cost averaging since 180$ on mstr, and don't plan on selling them or btc for many years into retirement.