Here, for your comparison, is some Frankish stuff imitating a Classical manuscript. But it’s a Classical script and it was brought here by Roman missionaries and those who followed them and to Ireland by the Romano-British and so on. I will grant you that as available now as Celtic Hand Font or whatever it is where you find it it tends to have what a palaeographer would call “Insular symptoms”, implying quaintly that to be written by people from Britain (be they Irish, Scots, Pictish, Brittonic tending to Welsh, or, dare we say it, English, since all their hands looked quite similar) was a kind of disease that a proper script would ideally remain free of. Those are half-uncials and they date back to Roman times. Oh, the heritage! Oh, the misty-eyed tinge of Oirish antiquity! NO.
Screen capture of a websearch for 'Celtic font' images