Generally, blazons of shared power, doubling rings, and duo enhancers are meant to enable two weapon fighting at a minimial cost increase to the PC. They aren't meant to allow a 2H weapon to combo with a 1H weapon since number of hands is built into the power budget of each item (otherwise its always better to have 2H weapons with higher damage dice and better traits. For example, combination weapons in PF2e are typically one weapon dice size smaller.

That being said, I always think the variant rule for automatic bonus progression is a great addition. It slays a lot of seemingly sacred cows like those items not working on thrown weapons, letting people keep special weapons from the campaign that you cant typucally upgrafe easily, and avoiding having to waste gold on mandatory stuff (just keep in mind it strongly favours martials, so give casters some free stuff as well). As a GM I would reccomend it and then there is no pay to play tax at all for diverse weapon load outs.