In the 1858-59 Griffith's Valuation of Londonderry (from RootsIreland), a George McDermott was living in Derry as follows:
McDermott George Sconce townland Formoyle Co. Derry
McDermott George Ballyrory townland Learmount Co. Derry
FamilySearch shows a George Dermott in Ballyrory townland in the 1820s in the Northern Ireland Tithe Applotment books.
Name George Dermott
Event Place Ireland
Event Place (Original) Ballyrory
Event Type Tax Assessment
"Northern Ireland, Tithe Applotment Books, 1822-1837", database, FamilySearch (https://familysearch.org/ark:/61903/1:1:4GF2-G3PZ : 13 January 2020), George Dermott.
It's not clear if this is your George, but it might be.