I’d check out the HyperX Cloud/Cloud Core/Cloud II/Cloud X. It’s based on a clone of the DT770 called the Takstar Pro 80, and has a very similar sound signature to the Beyerdynamic pair. You’ll get the same style of sound and a removable microphone. Similar design, too, and really comfy ear pads.
The different models include different extras and all of them are relatively affordable. It’s sometimes also sold as the QPAD QH-90 depending on which part of the world you’re in. Hope that helps you out!