After doing a little more googling and working through the problem,

=SORT(LET(X,VSTACK(FILTER(F12:F27,(G12:G27>=80%)*(C12:C27="F"),""),FILTER(F59:F74,(G59:G74>=80%)*(C59:C74="F"),"")),FILTER(X,X<>"")))

seems to be giving the results that are expected.