Not that (ouch hoti) - but that (all' hoti). Sharp contrast as in Joh 7:22; 2Co 7:9; Phi 4:17.
We loved (ēgapēsamen). First aorist active indicative, but B reads ēgapēkamen (perfect active, we have loved).
He (autos). Emphatic nominative (God).
To be the propitiation (hilasmon). Merely predicate accusative in apposition with huion (Son). For the word see 1Jo 2:2; Rom 3:25 for hilastērion, and for peri see also 1Jo 2:2.