Problems with dual boot after linux pop os installation on a windows machine

I recently put a 128 GB SSD that i found lying around my house in my laptop. I then wanted to install Pop OS on it. I flashed it on a USB and did a Custom Installation.

The problem

I have a boot/efi partition on the one SSD and a boot/efi (of windows) on the other. I can boot into Windows 10 however I cannot get into Linux OR the BIOS(!!!) When I press F2 the Acer logo just goes blank and stays there forever.

I already tried to delete the efi/boot of Linux. I helped a bit. I can get into Windows and BIOS now. But in the BIOS I only see the Windows Boot Manager.

My laptop is the Acer Aspire 5 and I boot with UEFI.