If I click the link to share our Google Business Profile in Google Maps it shows the URL as g.page/MagicOfChristmas2019. Is it possible to change this short URL from my Google My Business Profile?”

The URL you are sharing is called GBP short name URL and it was automatically created when you created a short name for your Google My Business Profile.

Unfortunately, you cannot change it anymore as Google deprecated the short name in 2021. However, you can delete it and the share URL will change to a random group of numbers and letters. If you wish to delete the Short name follow this guide: How To Delete Your Google Business Profile Short Name

Be remarkable!
Professor M