I have finally found the root cause of the issue. After using different GRUBX64.efi and BOOTX64.efi binaries (this time from https://vault.centos.org/8.3.2011/BaseOS/x86_64/kickstart/EFI/BOOT/) everything worked normally and the large initrd was successfully loaded. It seems that used Grub 2.04 from Ubuntu had that issue.
Thanks! -Vuk
