Are you being serious?
Software o/s and SWIFT?
These are not cards, these are bluffs.
Dare. Double Dare.
They will do nothing.
Right, these things in the end are just nuisance. Costly nuisance, yes, but they can be replaced in a few months. The industrial capacity to build much of what the world needs? That'd take decades.
As for China's response to the Huawei sanctions, it's not a matter of offense vs defense, it's a matter of difference in strategic paradigm. The American paradigm is to weaken the opposition on its way to victory, so from that perspective the opponent's response can either be defensive (i.e. reducing the weakening effects of American actions), or offensive (i.e. take actions to weaken America).
However, China isn't playing that game. China realizes that a great nation such as China or the US cannot be defeated by external actions, nor can victories be achieved through such actions. What such nations do to one another is at best adjunctive, but never decisive. What is decisive is what happens inside each nation, and China used the Huawei sanctions to instead help build itself up into a nation that's self-reliant on the most cutting edge tech such as semiconductor manufacturing and AI.
It's not so different from actual warfare when one side sees the taking of territory as a sign of success when the other side sees the destruction of the enemy army as a sign of success. For now, at least, both sides have doubled down on their respective strategy. The US has relentlessly attacked China with more and more sanctions, probably more tariffs, and probably more forced divestment, decoupling, etc. I wouldn't be surprised if OS bans and/or SWIFT bans will indeed be unveiled during Trump's term.
China's response, IMO, will continue to be neither offensive nor defensive, but with a focus on self-improvement. Divest Tiktok or ban? Take it, and China will use the proceeds to build a better app and make Tiktok the next Google+. Ban Huawei from SWIFT? Do it, and China will use the opportunity to promote CIPS. Ban Xiaomi/Oppo/etc. from Android? China will hasten the adoption of Oxygen and Harmony. Of course, the US will see these actions through their own lens, they'll be seen as offensive or defensive actions, with headlines like "the invasion of Chinese OS" or "Chinese banks scramble to rescue Huawei". However, rest assured, the Chinese objective will only be to strengthen itself because to China, that's the only path to victory.