The 10th Amendment has been historically neutered over the years, as the federal government has gained more power. Here it probably won't provide much use in defending against CBDCs. I'm not up on this stuff, but I am pretty sure the Supreme Court has interpreted Congress's right under the constitution to "coin money" to mean its right to regulate currency. I believe the thrust of these state laws are focused on the states' right to have taxes, fees etc paid in any way they wish. This is probably a gross simplification!