Forbid the sync if the Product is already synced
To forbid a Product sync you need to perform the next steps:
Step 1 Create a new Product
Go to Magento admin panel - Catalog - Products - Create new product
Check that product started to sync
go to Magento admin panel - Salesforce - From Magento Queue
Click Filter - type Magento Product ID and Apply Filter
Step 2 Modify the Product
Go to Magento admin panel - Catalog - Products - Edit created product
Scroll to the Salesforce tab
Switch the “Disable sync“ toggle to Yes
Save product
Step 3 Delete the Product in Salesforce
Go to Salesforce Org and Open Synced product
Remove Salesforce Pricebook entries and Salesforce Product on Salesforce Org
Step 4 Delete Salesforce IDs
go to Magento admin panel - Salesforce - Salesforce ID Mappings
remove Salesforce Product and Salesforce Pricebook entries IDs
Step 5 Delete related records from the Queue
go to Magento admin panel - Salesforce - "From Magento" Queue
delete related product records with Errors and in Schedule status
Step 6 Refresh grid
If the Product grid contains a Salesforce link for a forbidden product you need to refresh Salesforce columns data
go to Magento admin panel - Salesforce - General Configuration - Advanced tab
Set “Refresh grids“ option to Yes and Save Config
Go to Magento admin panel - Catalog - Products - Re-sync product
As result, no records are added to “From Magento“ queue and the product is not being synced.