or King Charles might decide to deny the title to his brother, or King William could deny his uncle when his father predeceases the Queen.
No, depriving a title takes an Act of Parliament.
https://en.wikipedia.org/wiki/Titles_Deprivation_Act_1917
Once granted the title is governed by the Letters Patent creating it.
I misread your comment.
In theory as King the Prince of Wales could choose to not grant the title. But I’m pretty sure they got his approval for the plan, since he would be the one granting it.
It is his brother after all.