You must not have been very good at geometry proofs in high school. Even though yes, both are true at the same time, one can’t know that initially because one leads to the other. Descartes couldn’t conclude that he was thinking until he had concluded that he was doubting.
He literally said, “I doubt, therefore I think”, and you say he was not thinking? I feel like maybe you’re not thinking.
If you’re sure of one thing and the conclusion of that surety is believing another thing then you are sure of both things.
You must not have been very good at geometry proofs in high school. Even though yes, both are true at the same time, one can’t know that initially because one leads to the other. Descartes couldn’t conclude that he was thinking until he had concluded that he was doubting.