I agree with you that no reason to be panic now but disagree with you that moving bitcoin to an account on Coinbase Prime does not have any risk of selling now or in future. This movement can serve as moving to a third party custodial wallet but in future, it might be sold by the owner of these bitcoins, the US. government.
It's more realistic to assume that these bitcoins will be sold, just a matter of time, when it will be sold only. Assume it will be sold, you will see no reason to panic as in Bitcoin market, there are buyers and sellers and many bitcoins changed hands on daily basis.
Compared to what Germany sold, it's not that much, and it probably won't affect the market. For most governments, Bitcoin has no particular value, especially considering that they didn't buy it, they confiscated it. Sometimes they decide to sell some of their Bitcoin when they need to, but on a national scale, these funds are insignificant to them. If they move it, it means they have plans for this coin. My opinion is that in this case, it would be better if holders who don't understand the value of Bitcoin (like some countries) sold it, and let it be in the hands of true holders.