Sure thing!

I'd be curious to know, however, under which legal figure the Treasury - or any other US Federal State entity - would currently be holding Bitcoin in a "stealth" fashion.

The most probable hypothesis, imo, is that the US government and the EU will seize almost all custodied bitcoins during the coming financial collapse (eventually paying them, but with a substantial discount), and try and get their hands even on the self-custodied ones, to handle them over to the CCP's (Central Clearing Parties). That "power of the Law" allows them to not have had to stack any significative amount of sats up to that future citizens & companies expropriation. 1933 & 2020 showed us they're perfecty capable of doing that.