Fedora will hide grub menu by default only if it's the only OS on your machine (i.e. It doesn't affect dual-boot or hidden grub menu in any way too.
I have many examples of both BIOS boot stanza or UEFI boot stanza (most just a chain into ESP), but none for any type of Android system. Once you start booting in one mode you cannot change.
Re: Windows 10 and Phoenix OS dual boot - troubles with GRUB.