Starting point: where you left off with Astra (an S from two faceted halves, like two open spanner heads, with a printed texture). Six ways to push it. Each card shows it big, at real small sizes (16, 24, 32px), reversed, and in the palette. Pick, mix bits, or say what's off.
Astra's S with the texture taken off: faceted outside, smooth S inside, one colour. The version that has to work everywhere.
The same mark with a stamped-ink finish like Astra's, for packs and posters only.
The inside goes angular too, so the whole mark looks like a machined spanner head.
Outer corners eased slightly: friendlier, less hardware-store.
Halves pulled closer so it reads as one letter, less as two pieces.
Smaller openings inside, so it holds up at 16px and on a tiny cap.