Russia being able to source silicon for their rockets was not enough of confirmation that sanctions are just a PR tactic along with minor inconvenience?

That Russia keeps sourcing Western chips for their rockets does not mean sanctions are “just a PR tactic along with minor inconvenience”. By forcing Russia to buy chips through intermediaries, each of which marks up prices to turn a profit, sanctions (a) drive up their cost, thus limiting what Russia can spend elsewhere, and (b) improve the negotiating power of the states harbouring those sanctions-evading intermediaries at the expense of Russia’s, which further weakens their already shaky international standing.