we should have already seized all Russian assets!
Siezing the assets of other nations - yes, nations, plural - will further erode the trust the USD needs to remain as the world’s reserve currency.
And, for goodness sake, a prerequisite to siezing anything from a nation must be an official declaration of war on that nation by the US Congress, following a request by the President.
There are rules of conduct between sovereign nations. The US has been playing fast and loose with those rules for decades.