https://support.chess.com/article/1257-how-can-i-play-with-a-dgt-board
Have you tried using the Chess.com website? The settings from the above look like the website settings.
https://support.chess.com/article/3599-how-can-i-play-with-my-dgt-board-on-android
There is no Help page offered for Mac users. The above link for Help for Android users talks about enabling the app to use Bluetooth. Have you done that?
If you look through the forum, people have had troubles connecting their Apple devices with DGT. https://www.chess.com/forum/search?keyword=dgt+mac
Have you tried using a Windows/ Android device?
One thread was started by a user who put together his own solution- https://www.chess.com/forum/view/chess-equipment/new-dgt-for-chess-com-macos-app-unofficial
It has not been officially reviewed as far as I can see but a number of people report finding it helpful.
Hello, I would like to ask you for help. I got new DGT Pegasus board and unfortunateIy I had no succes to connect ChessCom with the board. I watched some YouTube videas - people there connected Chess Com with the board in ChessCom app, in section “settings” - “connect board”. But unfortunatelly I have not that offer “ connect board” in my ChessCom app in my phone or Ipad. Do you have some advice for me?