beyerdynamics mmx 300 pro?

I bought the mmx 300 Pro, but currently have the problem that what I hear through the headphones is also being transferred to my microphone. It's not a strange connection; the microphone is actually so sensitive that it also picks up what the headphones are outputting. Mouse clicks… It picks up everything even though it's positioned directly in front of my mouth. I'm currently comparing it to my Logitech G Pro X by just recording sound, and with the old mic I don't have any noise or this problem, just like with the Beyerdynamics. Why is the microphone so sensitive? Would an external sound card solve this?

Some information:

No microphone amplification, otherwise it would be much worse

Motherboard: MSI Pro Z690-A WIFI DDR5 (Realtek Audio MSI is used for sound)