To use two chainrings on a gen 3 with a 8-10s cassette, no one in this thread has replaced the Hollowtech with a square taper BB and could tell me the axle length I should get?

In the front, the chainline is ~50mm

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Edit: Would a 122.5mm work for use with a dual chainring?

https://www.birdybicycle.com/product...-foldable-bike