This is very true. I've personally observed two households where one member had some sort of very nasty flu thing with a dry cough, fever and breathing issues

This is very true. I've personally observed two households where one member had some sort of very nasty flu thing with a dry cough, fever and breathing issues (likely covid but no test available) and other members were just unusually tired and with a tickily throat. The later could be classed as asymptomatic and would never have considered covid but they clearly had some symptoms.