Need help Manjaro stuck at 93%

Hi, I bought an iMac 27” 2020 and I’ve got problems to install linux in dual boot in general, so I tried manjaro. The installation stuck at 93% (grub-installer) even if I manually partitioned the disk myself!

I please ask for help!

I disable csrutil et allow my “T2 chip” to boot on external drives if someone ask

I would advice to have look here: Mac - ArchWiki and install the boot loader manually. I guess atm the manjaro installer don’t support iMacs.