Removing the title of Prince would involve King Charles issuing a new Letters Patent defining who is entitled to be called HRH or Prince/Princess (the current definition of HRH stems from the Letters Patent issued by George V in 1917). I think Charles is unlikely to do that, partly because he is more reluctant to act in general (hoping Andrew will do the right thing on his own?), and because it would open up a can of worms about removing other HRHs (Harry and Meghan for example, who are not supposed to be using their HRHs but did not have them removed, and even people like Beatrice and Eugenie who have, and use, HRHs but live private lives and are not working royals). I fully expect William will issue a new Letters Patent when he becomes king, though, possibly removing the HRH from all but the direct line of succession.