GRUB for chainloading opencore and windows?

Hey guys, I installed windows 11 and macos sonoma on the same drive recently. I signed the OC files and updated variables so UEFI SecureBoot works. The thing is, I used different EFI partitions for installing windows and OC. Therefore I have hidden the NTFS drives on OC using scanpolicy 2687747 and hidden the picker and it boots straight to macos. I currently use the bios picker to select between windows and macos (so no ACPI gets injected to windows). Many people use this PC, and most of them dont know how to select the proper os using the bios picker. I want to install another bootloader such as GRUB to provide a GUI to select between macos OC and windows. I tried installing grub to the OC efi partition with LauncherOption enabled, but grub-install in Ubuntu live fails to detect EFI. How do i do this?