What happens if you take a wrench to those flats?
If you can properly ID the hub then you might find spares that allow the configuration to be changed to 135qr.
But if not there’s not really much to be done.
That's the next steps, my tools won't fit (flat slots too thin) but will borrow some come spanners and find out what lies beneath. Then either mod the piece, or find shorter replacement if it seems replaceable.
@Fforiwr started
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What happens if you take a wrench to those flats?
If you can properly ID the hub then you might find spares that allow the configuration to be changed to 135qr.
But if not there’s not really much to be done.