Probably you're not planning on selling these as you didn't mention that you were, but if anytime you did wish to then you could always submit them to Heritage Auctions, who'd either pick them up from you, or you could drop them into one of their offices, and then they'd be insured at their BTC spot price with HA handling the grading at PCSG for you with no risk to yourself, if you subsequently sold with them it's likely that you could negotiate to not be charged any seller's premium and to be guaranteed the spot price at least on the day (set half an hour before the auction approx.) plus 50% of the 20% buyer's premium.

So if say the bitcoin price was $100,000/BTC and they sold for $100,000 + $20,000 BP = $120,000 then you'd get $110,000 (less the grading/slabbing costs, and possibly some fees towards photography and catalogue printing)

If they sold for $85,000 + $17,000 BP = $102,000 then you'd get $101,000 (less possible costs)

If the bidding didn't reach $84,000 then HA would buy them in and depending upon what you arranged with them, either pay you the $100,000 spot price, or retain them on your behalf for submission into one of their future sales, this has been my experience anyway and the feedback which they gave me on my latest sale with them was that:

"it was definitely our smoothest and most profitable crypto sale we’ve ever had, so I consider it a great success"

If you wished to sell some with them, but also to have some of them returned to you after they'd been graded/slabbed then they may be amenable to that I expect, though you'd need to check with them about it first.