Ronnie21093 (npub1st2…2wu9) for releases that are only through the official licensed company, i tend to use mangareader (through tachiyomi). Seems like it has all the official english translated chapters (though it's hard to verify since it's by volume), and mangaupdates claims that all scanlators dropped the series
https://mangareader.to/arpeggio-of-blue-steel-1076