You also have to consider the impacts to the other countries who would comply with these sanctions. You need time for them to change or the impact will be too severe, and they will just ignore them.

This takes political and economic capital. If the US were to move too quickly- esp in something where other countries obviously don’t have the same motivation to act, they could just tell the US to piss off and form their own economic system- without the US in the lead. This is a matter of calculating which option causes the least burden for those countries along with a bit of a gamble.