Please separate the dynamic syncing of the browser components from the account's static info. Mozilla is far more sophisticated than that.
I must recreate the same list of the add-ons and dictionary lists, which is static info. Syncing is not congruent with static account data. The new account will always have the same user name, email, password, as it has been since the Arc settled on Mount Ararat.
I recreated the account perhaps 20 times over the past decade, just to remove sync errors.