There’s an app called Pro Compass for Watch - might be worth a look. There’s also this:
Which do you think is the absolute BEST Compass App for Apple Watch Series 4? (It can be paid or free) Thanks!
Incidentally, I was slightly puzzled by the reference to magnets in early Sport Loops on the support page. I wasn’t aware they used magnets.
The presence of magnets can affect the accuracy of any compass sensor. Apple's Leather Loop, Milanese Loop, and earlier Sport Loop watch bands use magnets...
The Compass app shows you the direction your Apple Watch is pointing, your current location, and the elevation.