When tested, human noses turned out be pretty sensitive:
One factor we might be overlooking is that humans derive a great deal of information from symbolic language as well as from our senses. When a dog sees a visitor who is acting suspiciously, he may sniff him out and study his movements to determine if he poses a threat. A human can ask around about the man’s reputation — and maybe find out if he has a criminal record… Perhaps, over time, we have tended to discount our senses as “subjective” in comparison with, say, a rap sheet.News, “The nose really does know, it turns out…” at Mind Matters News
Losing one’s sense of smell — as with COVID — is dangerous as well as traumatic but, relative to other senses, we don’t yet know much about how it works.
You may also wish to read: Has the human sense of smell declined in recent millennia? Researchers found that people with “ancestral” genes perceived various odors as more intense. To be sure that our sense of smell has genetically declined, we would first need to see whether concerted efforts to improve it were successful.