In the OS2 for Instant Brand Page there is now an option to directly manage the default sorting to the products that are displayed when the respective collection template is loaded.
To manage this option go to the Settings tab within the application interface
Scroll down to the 'Mapping Brands to Products' section and to the 'Default sorting' drop down.
Select the outcome desired and click on save
Brand links will not contain the respective sorting instruction. For example
https://<store name>/collections/3m?sort_by=best-selling
Note: The application of this setting will be Theme and Collection configuration dependent. Specialised sorting on the collection page may override this setting and default sort setting on the Collection itself will also override this link.