Hello there Cornelia2020,
We understand that you're having an issue connecting your Jabra Elite Active 75t earbuds to your new Mac. We have some helpful tips for how to find a solution.
We want to begin by making sure your Mac is fully updated to the newest version of macOS by following our guide here: How to update the software on your Mac
Next, try our steps here for what to do when you're unable to pair your earbuds: If a Bluetooth headset doesn’t work with Mac
Working with Jabra is also a great next step, and we've found some important information on your earbuds and a possible firmware update you may need: Jabra Elite Active 75t - Jabra Support
We look forward to hearing your results!