My suggestion is to seek help from your ENT. I’ve had Anosmia (inability to smell) for more than 30 years secondary to chronic sinusitis and asthma. I don’t know if bronchiectasis can cause the condition but certainly sinus problems can. During the early stages I would also experience smells that weren’t actually there, as you described. They were quite annoying. My current ENT (since 2019) prescribed a procedure whereby people with Anosmia can regain some sense of smell by systematically smelling a series of 4 to 5 strong essential oils (like peppermint oil) on a particular schedule. The procedure didn’t work for me, most likely because I had gone so many years with no smell. But it might be useful for you to look into via your ENT to see if it would help with Phantosmia. Good luck. I know how annoying this is.