Does Disk Utility create independent EFI for new APFS drive?

Drives do not get tied to one-another in any way.

On an Apple Silicon Mac, a bootable external drive is blessed by the host Mac to allow it to boot from that external. That "blessing" is written to the internal drive of the Mac.

If something happens to the internal drive on the Mac, that Mac cannot boot from any external drive.

burakcey05 wrote:

Thank you! So, just to be absolutely sure: if I format the new drive as APFS/GUID, it will create its own independent EFI partition and will not alter or touch the other connected drives in any way, correct?

I don’t think I fully processed what you were asking before as that would be wholly unworkable. The EFI is drive specific. I can’t imagine how you could require some other drive to hold the EFI of another.

I was trying to work out why you would ask that question and the only explanation was that you might have been confused about external startup drives on Apple Silicon. That has nothing to do with the EFI on the external drive (which absolutely must be there). In that situation, the internal drive doesn’t maintain the EFI of the external startup drives, but you absolutely must have a working internal drive to startup from an external drive on Apple Silicon.

burakcey05 wrote:

Thank you! So, just to be absolutely sure: if I format the new drive as APFS/GUID, it will create its own independent EFI partition and will not alter or touch the other connected drives in any way, correct?

Using Disk Utility to erase a physical drive will only touch that single physical drive.

Now, if you have an Apple Silicon Mac and are installing macOS onto that external drive, then the macOS installer may possibly modify your internal SSD since the internal SSD is necessary to boot even external macOS bootable drives. I honestly don't know what the macOS installer may do.

FYI, booting from external drives on an Apple Silicon Mac can be hit or miss. Apple still allows it, but it is not quite as simple as it used to be with the older Intel Macs. You need to read the following Apple article since it contains critical information for installing macOS onto an external drive when using an Apple Silicon Mac:

How to use an external storage device as a Mac startup disk - Apple Support