Linux with w10 - alternative methods?

Is this a fair summary of the possible ways to use Linux on a machine with w10 already installed ? w10p 1909 build (up-to-date), digital license, MS Account linked, single user.

Option 1:
With w10 shutdown use a Linux live bootable usb and operate the Linux system only from usb.

Option 2:
With w10 shutdown use a Linux live bootable usb and then do a full install from usb. Allow Linux to shrink w10 partitions and create its own and use Grub loader. Set choice of timed out defaults in Grub when presented with first machine boot screen.

Option 3:
With w10 shutdown and a second drive available. Do full install but change the location of the Grub loader and then use BCD to find Grub and present a blueBox option to boot either Windows or Linux. As per this post ...page 3 ...
How can I move windows 10 boot files to another drive to allow linux

Option 4:
As per option 3 but do not use BCD. Instead use the bios boot options to enable a boot-from list with a function key and select from that.

I have previously used the full install on Windows drive with Grub and also the second drive version with grub.
Currently on just usb live only, but leaning towards option 3 or 4.

As I have not used BCD before ... would welcome opinions.

There are several other options as well but you really did not explain what you are trying to accomplish. I triple boot Windows 10 with a couple of different distributions but I use my native motherboard boot selection menu, I do not use grub. There are also virtual machines and various other methods that you did not list, but if you want to use GRUB or EASY BCD or any other method that is your choice.

Virtual machine or hardware based are the two main options to choose from. There are several different methods within each camp to choose from, just explain what you want to do and people here can help you.

Thank you Bree & Rocky
Yes it is Pro version and no, had not considered VM.
Never used VM even though it is enabled on this machine and I suspect it has capacity to run it ( i5 + 16 Ram ).
Would be very interested to know more, can you point me at the good reading for VM please.

Want to use Gecko (previously used OpenSuse 11, 13 to Leap 15.2).
But these were primarily "get me out of trouble" installations and I am not a LInux sudo by a long chalk.

Just a personal preference to leave the Windows boot record intact (but do not distrust Grub in any way).
My thinking is that by having the Windows all on one primary drive and Linux on a second external drive I can see and keep a clear distinction.
Want to learn a bit more Linux and try a Linux dev server for some SQL table/query practice.
Testing conversion from MS Access only to Access/MySQL combo.
Already changed from RAID to AHCI with help from this forum so have tested Gecko usb and it now "sees" windows folders and files.

Assuming this is an uefi system. There have been reports that the Ubuntu installer ignores the user's choice of the disk to contain the Linux EFI partition. Theoretically, it should be possible to create beforehand an EFI partition on the other drive, and if the installer gets it wrong copy the misplaced Linux boot files afterwards to the the EFI partition on the other drive.

VirtualBox is open source and has a great support community. Oracle VM VirtualBox

It is quite easy to use and very versatile.

Thank you Samuria, seipo & Rocky.
Yes UEFI, and also agree that being unfamiliar with w10p and reading stories of updates/upgrades driving over everything I would prefer to keep the Linux on a second drive (worked perfectly well before, even after I messed up the locations for the partitions and had to dig myself out).
Will investigate those two VMs .....
Where would you recommend for the best reading about using/operating in VM environment ?
Soon to do inplace upgrade to 20H2 from iso and will be following Brink's tutorial .... everything crossed

I haven't dual booted in years. Virtual machines are the way that I pretty much run it all.

As others have said, hyper V is an option with 10 pro. I feel linux support might be better with virtual box. I personally use HyperV, but it's because I need wsl2 (windows subsystem for linux) and docker....and they require hyperV.

I have a UEFI BIOS and have Linux on same drive as Win 7. Windows and Linux are independent and the default OS on BIOS priority is Win 7. To boot from Linux I launch boot (F12) menu during post.

My suggestion is option 3 or 4.