Ok. Plz take a step back and explain with better details the issue and what you did to get there.
Your initial post clearly says "I installed garuda on usb 2 flash drive USING VIRTUALBOX".
What do you mean by that?
You burned Garuda on a USB stick while you were in VirtualBox? What OS was booted in VBox when you did that? Why did you do it from VBox?
Have you burned the Garuda ISO image file on that USB or a custom installation of Garuda that you are running in VBox and created your own ISO image?
Also as stated by SGS we will really need the output of your garuda-inxi, from your terminal window. This will give us details on your machine and installation which often help for troubleshooting.
(I cannot view your youtube link, not sure if my work network is blocking it or if everyone else cannot view it as well)
I think this is causing some confusion because VirtualBox is the name of something else--most folks here are thinking of the hypervisor for running virtual machines, but it sounds like you are referring to some software you used to flash the ISO to the USB drive.
The meaning of this is unclear, but your boot partition is typically mounted at /boot/efi (not /).
I couldn't view it either, I got a strange error message.
Our systems have detected unusual traffic from your computer network. Please try your request again later. Why did this happen?
Ok so you are on Windows. You know you don't need to burn the Garuda ISO file from VBox, you can do it directly from Windows with say Rufus application.
Second, when you enter your BIOS settings, do you see the Garuda USB listed in your boot sequence?
Third, since we don't know exactly what machine you run, we never know the type of hardware incompatibilities that can occur (distros have some different packages installed and don't all react the same for some use cases). It is often advisable to make sure you run the latest BIOS update version, although if Linux Mint was booting from that SAME USB stick but Garuda is not, I would hold off the BIOS update for now.
I think I start to underestand, you want to run as a normal OS (not as Live ISO) Garuda on a USB as if it was installed on a 512Gb SSD, but you want to have it on a portable USB stick.
Well first thing is the guy clearly says NOT to use USB 2.0 as it's too slow (around 17mins45sec of the video). You said you are using 2.0. So that's one thing there, maybe not what causes your problem, but still you should look at that.
So as asked above, when you boot into your BIOS Settings, do you see the Garuda USB in the bootloader sequence?
Garuda Linux is a bad choice for this type of USB-encapsulated system. In fact any rolling-release OS that takes a lot of updates will be a bad choice for a system that lives on flash media. Puppy Linux, MX Linux, or Peppermint OS like the guy in the video suggested would be better suited for this kind of project.
If you want to use Garuda Linux, please make a proper partition on your native disk and put it on the metal.