I wonder if this is different because it’s a mode of the harmonic minor though. We know for certain there’s not really a key signature for harmonic minor, so maybe different rules apply here? For example, this is a mode of B harmonic minor (at least I think lol I never committed the modes of harmonic/melodic minor to memory). B Harmonic minor wouldn’t have an A# in the key signature, so why would we pick a key that does for the modal interpretation? I guess by following your nice simple rule of “the fewer accidentals, the better” you’d arrive at the same answer.
While I think it makes sense to learn to read sheet music in plenty of contexts, I just never do it for rock guitar. If I have a score where there are tabs, that’s what I’ll read. Classical stuff, fine. They typically only supply the standard notation. But if I picked up a Barrios book where someone had tabs beneath the notation, I’d probably start with that and only look above if some fingering felt weird.
That said, I’m glad there are other people who care enough about “the right way” for sheet music. This is important stuff!