Nothing he does will affect his daughters positions in the succession though. Even if he takes himself out of the line of succession he can’t remove his children
Correct - they are HRH because they are grandchildren the monarch in the male line. The Wessex DC could also be HRH, but have chosen not to use it (parents' choice whilst minors, own choice thereafter)
You can only quit the succession for yourself, and any children who were not born at the time of quitting (ditto abdication - Edward VIII had no DC at the time, and was making it clear that if any DC were born to his marriage they would never join the succession). One someone is born, the place in the succession is theirs and only they can quit it (and I think only once adult)
Remaining question is whether the Duke of York will be removed as Counsellor of State (the people who can formally stand in firbthe monarch). Normally it's the consort (optional) and the first 4 adults in the succession. At present it's Charles, William, Harry and Andrew. Harry ought to be removed for the duration of residence overseas (not being domiciled in UK is a bar to acting in the role) and as Andrew has effectively been sacked, he should be suspended from the role.
That would mean Beatrice and Eugenie should take up the role, but they are not working royals. For it to be Anne and Edward, it would need parliamentary action. It's a bit of a mess!