If the US wants to make sanctions effective, they need to add russia to the state sponsor of terrorism list, start applying partial secondary sanctions and greatly expand direct sanctions against relevant executives.
This is not related to tech, but one example is the Austrian Raiffeisen bank. They've been "leaving" the russian market for 3 years. Personally sanction their executives (without any additional warnings) and I can guarantee you that they will stop playing dumb.
Embargos will always have limited effect and legislators know that. If the Russians pay "just" 10% more for GPUs, that's not sanctions failing, but sanctions working. They're all about making things harder and/or more expensive to get. If things are too easy to get, you tighten the sanctions, i.e. cut supply for the/some companies in question. Is that the case tho?