Just wondering if after a year it's time to buy my next phone or are there other people seeing this issue too?
Probably, Pixels and iPhones have best cameras/software, but I wouldn't buy new phone just for this
I think that scanning QR codes depends mostly on software and camera device that are used.
If one of this components are bad or low quality you will have issues with scanning QR codes sometimes, especially in conditions that are far from perfect.
I also found out there are so many QR codes, and they are not always compatible with each other, or they can be more or less complex.