Thomas refutes your objection in
I-22-2. He states your objection as:
“Objection 2: Further, a wise provider excludes any defect or evil, as far as he can, from those over whom he has a care. But we see many evils existing. Either, then, God cannot hinder these, and thus is not omnipotent; or else He does not have care for everything.”
He concludes his answer to that objection: “It would appear that it was on account of these two arguments to which we have just replied, that some were persuaded to consider corruptible things—e.g. casual and evil things—as removed from the care of divine providence.”
In
the first article I linked, Thomas actually says “we can admit the existence of fate: although the holy doctors avoided the use of this word, on account of those who twisted its application to a certain force in the position of the stars.”
On your point about laws of nature, which Thomas calls second causes, he says: “We must therefore say that fate, considered in regard to second causes, is changeable; but as subject to Divine Providence, it derives a certain unchangeableness, not of absolute but of conditional necessity. In this sense we say that this conditional is true and necessary: “
If God foreknew that this would happen, it will happen.” Wherefore Boethius, having said that the chain of fate is fickle, shortly afterwards adds—“which, since it is derived from an unchangeable Providence must also itself be unchangeable.””