Is current Gothic normalised transliteration correct or not?

Is current Gothic normalised transliteration correct or not?

I know that

a normalised transliteration of Gothic "au" before /r/ is /u/,

but I think that

normalised transliteration of Gothic "au" before /r/ is /u/,

but before /rn/ is /ɔː/ as before vowels


"ai" has e-grade and others
"au" has o-grade and others


I can accept that Gothic "au" and Proto-Slavic (Russian) "ь" е in following word list are cognate only by o-grade and e-grade intersection (because o-grade and e-grade have intersection in Proto-Slavic (Russian)):

haurn *sьrna серна
kaurno *zьrno зерно
þaurnus *tь̀rnъ терние