Have you used them?Try blade tech.com
I ended up with the Blade Tech Signature singles. They'll do nicely for my purposes.BladeTech https://blade-tech.com/products/signature-series-double-mag-pouch
seems to be the standard for the gamers without getting into the real pricey ones
I did a quick search and found these
IPSC USPSA IDPA Competition Multi-Angle Speed Pistol Magazine Pouch Mag Holster 6018996985458 | eBay
I have their International holster for the G19. It's very good stuff.