At least for US purchases: If you purchased TurboTax for PC and Mac and created an account with intuit.com, Intuit might have a record of your purchase. If you bought the disks off of Amazon from another seller, I don't know if that product can be downloaded except by the original registrant/purchaser. If you bought the CD from an authorized seller, you can probably register your software purchase with Intuit. I would try calling their sales number or their customer service phone number, which you can eventually find on their support website.
For instance, I used to have TurboTax mail me a copy of the CDs every year by subscription. Now I am able to go back onto intuit.com to My Account, poke around through my past purchases, and download the Mac DMG file to download for those years, back to 2014. It's not that easy to find but it's there.
I just recently downloaded 2016's DMG file and installed it no problem on my 2019 Mac. There should be a similar downloadable version of the CD available for 2020, given that Intuit apparently sold a CD version - as you mentioned, if the OEM product packaging says "for PC or Mac", you should be able to install it.
See if you can find this option. You can't install a PC installer file on a Mac as-is, but there should have been a DMG file or similar installer on that CD.