A bike smaller than is recommended
To me "58cm or so" means, "58cm, maybe 56 or 60." It doesn't mean 54cm. If a professional has said you should be on a 58, you should heed that. 4cm in the wrong direction could place your knees too far forward of the pedal spindles and be less efficient or even cause repetitive stress injuries to your knees.

Instead, try fine tuning your current bike which sounds like is "almost right". You have several options to make the 58cm bike shorter: moving the seat forward on the seatpost, replacing the seatpost with one that has less or no setback, and/or swapping out the stem with one that has a shorter reach. If it's an old Peugeot with a threaded stem, you can also adjust the handlebar height.

The combined cost of making all of those changes to the 58cm would likely be less than buying a different bike.