Has anyone tried to
use dbaPlatform to schedule Posts on Google My Business? I think the cost is pretty reasonable at $1 per month, and it works with multi-location and franchise brands. You can create an account on dbaPlatform at no cost, but once you want to actually make the post you have to pay.
Here's a demo video on YouTube of how someone can
schedule GMB Posts for "franchise" brands (
note this video was made in Sept of '18 so the interface has been a bit updated for the better since that time but whatever).
Full disclaimer, I own part of the company and try not to self-promote too often but it seems like a lot of folks following this thread will find it helpful