I saw a recommendation to use Firefox’s container extension https://support.mozilla.org/en-US/kb/containers, but it’s disabled in private browsing windows, and I always use private browsing windows.
Then just… enable the containers in private tabs? The option is right there in the extensions menu.
That’s exactly what fudging rolls is though… “I’m not fudging, I’m just changing the result of the dice when it isn’t fun”