[Feature request] Automatic Mode: Clear default container cookies on exit?

[James-E-A]

I keep many tabs open, virtually all in unique temporary containers, and have Firefox set to restore them all on startup.

Sometimes, when starting up the browser, all these tabs are converted from temporary container tabs to tabs in the default container (seems to be a consequence of the containers being purged). I've now got a huge pile-up of 50+ tabs all in the default container, allowing the ad actors to easily associate these many tabs' activity with each other.

I'd like to request a sub-toggle (probably should be opt-in) for Automatic Mode that will clear just the default container's cookies and site data on startup, and/or a button to do the same manually.

Such a feature would help prevent intermittent failures of Automatic Mode from accumulating over time into a "bilge" of high-quality correlation data in the default container, without having to take the drastic measure of clearing all cookies and site data browser-wide (as e.g. LibreWolf does by default), which would destroy the utility of permanent containers (avoiding the nuisance of signing into Google or other 2FA-enabled accounts each day).