A Land Far Away

Is it possible to bring about the PnP rule about non proficiency with weapons using the following?

Create an item, nondroppable, always active, that gives all weapon proficiencies, but at the same time, gives a -4 to hit.

Then create a second non droppable item that gives +4 to hit with selected weapons, eg the ones each proficiency allows, being a custom item that DM's can issue. Have the item personalised so it pertains only to the correct character.

I would give it a go myself, but learning to script is just not viable timewise for me right now.

An additional boon would be that we can then have proficiencies for specific "exotic" weapons, as per PnP.
Although given the backlog of work, and the limited number of workers (who are underappreciated (thanks, guys! (and gals! ))) this will probably end up on the "would be nice" stack.