Not mentioned: maybe dump your ancient, near zero cost coins into a treasury security origination for fiat spot coin share cost basis without realizing any cap gains?
In-kind redemption is now a thing, at least for the "authorized participants". Is in-kind payment for newly issued shares also a thing? I seem to remember it would only be possible for the authorized participants on initial fund creation.
Your 10k coins from mining 200 blocks in 2010 magically become the property of your caymans corp, which merges with a US-listed spac vehicle to seed its treasury; 10m shares of common are issued and marketed at $118 per: those become yours with this cost basis barring wonky stipulations regarding holding period, deal terms, structure, etc.
Coins are now locked up in that corporate structure