I've added an "Multi-Account Containers Isolation" feature to the Temporary Containers Add-on. Enabling that will only allow Websites that are assigned to "Alwa

I've added an "Multi-Account Containers Isolation" feature to the Temporary Containers Add-on. Enabling that will only allow Websites that are assigned to "Always open in" with Multi-Account Containers to load in their container - every other request will automatically opened in a new Temporary Container. There's also a discussion about implementing such an Isolation feature directly in Multi-Account Containers.