Bards can use a number of musical instruments in combat, but I think a disproportionate number are specializing in Lyre so they can use the Lasallian Lyre artie. I was hoping to propose that every instrument that a Bard can use be made into an artefact identical in function and cost to the Lasallian Lyre. So, a 500 cr Lasallian Flute, Lasallian Mandolin, Lasallian Harp, Lasallian Lute, and of course the Lasallian Lyre. and also that an inexpensive option be attached to all such artefacts so one can be switched to another. This would enable bards to use any musical instrument even if they want the powerful effect of Lasallian Lyre. I cannot see any OP issues, it's mainly a flavor issue. And I cannot see why any Bard would argue against this being done, because it gives more options, is simple to implement, and detracts literally nothing from any part of the game.
I think there might be the objection that all these options needlessly clog up the Artie shop. So, why not do what was done with Races and those Morphing Weapons? Sell the person an "unspecialized" Lasallian musical instrument, add an option to the item similar to racial specialization, and the unspecialized Lasallian item just morphs into Lyre, or Flute, or whatever. And, there is some sort of option, with or without cost, to later morph it into another instrument, if needed, morphing-weapon-style, (without cost,) or reincarnation style, (with cost.) That WOULDN'T clog up the artie shop.
Thank you for reading my idea.