boot – No grubloader menu after installing Ubuntu Budgie with windows 10 Pre-Installed (Different Drives)

(advance sorry about my English. I’m not a native English speaker)
This is the First time I’m doing the Dual Boot thing, and I am new to Linux as well. I followed some YouTube procedure. Everything went well. But the grub loader is missing. When I turn on the System it directly boots into Windows 10.

During startup, if I press F11, then windows 10 and Ubuntu shows up there in the boot options menu, and i can log into Ubuntu no problem. and the grub menu also shows up before it boots into Ubuntu OS and both Ubuntu and windows 10 is present in that menu.
But it doesn’t appear automatically without pressing F11 during Boot up process.

I tried to reinstall/repair the grub menu by inside Ubuntu by using boot-repair commands(Recommended repair option). It didn’t work for me.

I am using an MSI B450 motherboard and I tried to change the boot order by moving the hard drive in which I installed Ubuntu, but there only hard disk on which I installed windows 10 shows up and the other hard drive doesn’t appear at all.

when I logged-in to windows 10 I opened advanced system settings and checked default OS, there only windows 10 option is there. Ubuntu is not there either

Please help me with this problem.