How to create a custom GRUB2 as similar to RHEL7

Hi,

I would like to create a custom menu entry on RHEL 8 as similar to the article https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/sec-customizing_the_grub_2_configuration_file It seems the new way to read menu entry is different in RHEL8, Could anyone help me to add a custom entry to the RHEL 8 image and it should boot with all .ova upload without throwing grub issue.

Note: My intention is to provide a .ova which should be uploaded to any ESX machine and booted without throwing grub issue