We all have our own problems when it comes to the stutter. A lot of people believe it's to do with trauma and such. If that's the case, maybe you developed a problem with authority figures ? If it happened over covid, I'd blame covid for it tbh. The best thing I can advise you to do is see a speech therapist or a therapist. Maybe even both and hopefully they can help you further. Other than that, just try the usual techniques and maybe there's some you don't know about. Try them and see a specialist if you can.