I am running macOS Big Sur version 11.5.2 on a MacBook Pro and just bought a Reshow cassette tape to mp3 converter. I downloaded Audacity 3.0.4. and Lame software as specified in the Reshow instructions. I have tried to convert a cassette tape recording but Audacity does not seem to record any of the sound (I have made all the suggested adjustments to ensure the volume is high enough to be captured). The sound monitoring function shows strong green volumes are being received but the blue wave sound lines are flatline. Further, neither Audacity Preferences nor my System Preferences appears to ‘see’ / recognize the Reshow device. Except curiously, in my System Preferences - Sound screen, the name choice “USB PnP Audio Device” does appear intermittently for a second or two. When I attempt to select it by moving my cursor toward that row, the USB PnP Audio Device choice disappears, then may reappear as I move the cursor away. Seems to have a mind of its own. Any thoughts?
Is this what you bought? https://www.amazon.com/Cassette-Converter-Portable-Earphones-KALULI/dp/B07T2YR4L6/ref=sr_1_11_mod_primary_new?dchild=1&keywords=super+usb+cassette+converter&qid=1630971738&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sr=8-11
Very, very few people get these to work reliably on a Mac. I hope you saved your receipt.
One thing I have asked people to try, but no one ever does, it to try it with batteries. Let me know if you try this.
Yes, that Reshow product is what I bought. And I did add batteries about halfway through my trials and tribulations but that didn’t make a difference to my issuee. I will be sure to remove them before I return the device to Amazon. Thanks for the quick reply.
Thanks for the report about the batteries not helping. 
Some people have good luck using a Behringer UCA202 or 222 interface. You might even be able to use that with your Reshow.