SD card not detected through a USB hub on a newer intel-based Mac
You won't see it in disk utils or finder until it is mounted. The primary causes of this are (in my experience):

Inadequate power in the USB-C hub. Typically, power needs to pass through the hub rather than the hub being a stub. (Sorry, couldn't resist the rhyme). I think I saw the hub plugged in by itself...
Now, that said, with nothing else, that shouldn't be a problem, but try it. It's quite common with USB hard drives that are USB powered.

Bad connection or damaged card. Check the card contacts, make sure they are clean and undamaged.

A corrupted card (or a card image that looks corrupted due to 1 or 2). Check to see if an fsck process is running on the card; this is done for 'dirty' disk images that aren't known to be cleanly ejected. It won't mount until that completes. If the process is hung, or dies repeatedly, then it's likely that it's having a hard time reading the card, again, see 1 and 2. If it's hung, kill it, and eject the card and try again.