MacBook stuck in Internet Recovery Mode

I managed to wrongly format my SSD into MBR (Master Boot Record), since then my Mac is stuck starting in Internet Recovery Mode over and over again and I also can't run the Terminal command for example (CMD+S) to erase the SSD by hand.

There would not be any problems to recover it with the Internet Recovery Mode, but as soon as I choose my WiFi network, it will run on an endless loop. Neither I see any progress bar or ETA for the recovery. The process looks like this:

I once did run it for 24 hours, but except that fans was very loud, there was no process at all. I also used a different WiFi to see if there was a change (which was not).

The only thing I'm able to do is pressing the 'Option' key to boot from my USB but this is not working as well. It look like this:

As soon as I select the "Install macOS Mojave", it will start again the Internet Recovery Mode and it will run on endless loop, again.

Could be the USB fault for it? But if so, why the Terminal is not working?

You can try installing Ubuntu (or any other Linux distro) onto a USB. Then, start a live session. Open GParted and reformat your iMac’s HDD or SSD to GUID. After that, try booting into recovery mode again.