Ebay Income on 1099-k & selling old stuff

I'm sure this is going to be a popular topic when the 1099-ks start coming. 

Here is my situation...

 

My husband and I have kept all our old LPs from the 60s/70s/80s and have started to sell them on ebay.  Much to our surprise, we are getting a good amount of money for them and will be getting a 1099-k for 2022.

 

We purchased all these LPs, but of course, don't have any receipts for them.  I don't know if we're classified as hobby sellers or something else.  We have very few expenses related to the sales - fees & postage, and that's about it.  We have no way of determining their cost.

I  have also read that the 1099-k will be the gross amount of the sales, which will also include sales and shipping but NOT include returns or cancellations.

This is going to be a record keeping nightmare if I have to go in and figure out the values that shouldn't be including in income, such as the returns/cancellations.

Are we all going to get audited because the 1099-k doesn't show only gross income?

How are others preparing and handling this?