Hello,
Since the rear triangle on that folding bike prevents the front derailleur from moving totally to the inside, the chain rubs slightly against the derailleur's fork when on the inner ring. No biggie, but a silent bike is nice.

To add a spacer on the drive side and move the bottom bracket axle a bit to the right, I thus need to undo the BB (plastic) cups. Worth trying before buying a BB with a longer axle.

Before using more force, do you confirm 1) it's the right tool, and 2) it's the usual threading on both sides (lefty loosey)?

Thank you.