Gestalt,

I'm glad you were able to get the covid booster and influenza simultaneously without any symptoms.

For anyone else, I believe it is recommended to have influenza a week after covid booster.

I had no side effects from initial Pfizer doses, but received covid booster and influenza simultaneously with a day lost to malaise and generalized myalgia.

I would recommend following physician/pharmacist recommendations, unless trying to get out of work or an undesired family reunion.