Some Irish Protestants were descendants of recent immigrants from Britain, others were descendants of Irish converts from Catholicism.

Consider for example, Edmund Burke (the famous conservative philosopher) - he was born in Ireland to a Roman Catholic mother and a Church of Ireland father; his parents raised him Anglican and his sister Catholic - this was not an uncommon compromise for middle class Irish families of the time, discriminatory laws limiting career and education opportunities for Catholics largely didn’t apply to women who were excluded from careers and higher education irrespective of their faith. It is unclear whether or not his father, a lawyer (at a time when Catholics weren’t allowed to practice law) had converted from Catholicism, or if one of his ancestors had - but given Burke’s paternal line came from an old Hiberno-Norman family, descendants of the 12th century English invaders who over the following centuries assimilated to a Gaelic identity, it is obvious that one of his patrilineal ancestors must have switched from Catholicism to Protestantism at some point.

A fair point, but I think the "Old English" people (Hiberno-Normans) are not usually considered part of the protestant ascendancy.

Wolfe Tone was a member of the Protestant Ascendancy.

https://en.wikipedia.org/wiki/Wolfe_Tone