Would I have to send all SAT + subject tests if I only want to send subject test + ACT to the UCs?

The first time I took the SAT, I got a low score. I took the ACT twice after that and got a good score. I also took 3 subject tests, 1 physics and twice math 2. The UC says they want all SAT scores, but what if I don’t want to send in the SAT score and only want to send in ACT + subject tests instead?
Should I just select the score I want to send? (although they have said all scores)

No, if you are sending subject tests to a college that forbids score choice, you have to send your ACT as well.