Dualboot on ROG Ally X

I'm still trying to dualboot Windows with Bazzite on my Ally for quite some time now. following this guide: https://docs.bazzite.gg/General/Installation_Guide/dual_boot_setup_guide/ but it always fails when creating the partitions. I already asked for help in this discord according to this problem but nobody was able to help me because this issue is unknown. when trying to add the EFI partition with mountpoint /boot/efi I get this error:

Dual Boot Preliminary and Post-Installation Setup Guide - Bazzite D...

Bazzite is a custom image built upon Fedora Atomic Desktops that brings the best of Linux gaming to all of your devices.