@Linuxlite76 I've always heard of the Pixel 3a port being quite good. I doubt this is something that an update would fix, as it sounds like non-standard behaviour.
I wonder if it could be a hardware issue. Have you tried other headphones? Cleaning out the jack?
I've replaced headphone jacks on other phones and found the repair to not be too difficult, but I'm sure it depends on the phone.