When I get cold/sneezing (the usual non-flu winter sickness) I cough much more since covid, more thick sputum created in the lower part of the throat. Talked with few people around and they confirmed they feel similar effects.

Allergies could easily be another area where effects can be subtle but permanent in some individuals. My father's hair got almost completely white after he almost ended up on ventilation for example. We as family with 2 kids (back then babies) had covid at least 11-12 times so far (confirmed by tests, wife is a doctor), plus few other probably-but-not-tested. Most recent one last autumn was like immunity went to 0 again, was coughing away nasty stuff for another month. I am glad I just survived all that, some of that was mild and some was pretty harsh on body and mind.