You should be able to upgrade to CSP, (depending on your credit line). But you won’t get the signup bonus & you might be charged the AF IINM.
You can upgrade even with a lower CL, and you'd still be able to get the SUB in the future as long as you don't have the card at the time, and didn't get the bonus within 24 months
And you will pay the AF
ETA: although within the first year you won't be able to upgrade.