This is ridiculous! I recently migrated our site from Wordpress & WooCommerece and although not ideal I could autopublish to Facebook and Instagram daily. The fact that we need to now go into the account daily and force publish to Facebook Shop, Instagram, Buy Button, and Google Shopping is just plain crazy. Our inventory changes constantly, really feel like this was a major step backwards in functionality. Lots I like about Shopify but this is a big mark in the negative column.
Although this problem yet to be solved with adding good API endpoint (or graphQL permission option for private app). There are new way to add/remove visibility on different sales channels in bulk is possible through admin tools. Here how to do it:
1. Select all products (or some), click "More actions" > "Add available channels"
2. Select Channels and click confirm
This will NOT have instant effect, changes will be done in few moments