No, you cannot "pop out" the original SSD and swap in a new one and boot the system -- you must, one way or another, install the OS to the new drive.  That means either a clean install from a flash drive made with the Microsoft Media Creation Tool, or making an image of the existing drive  to external media (no, a 32G flash drive isn't large enough unless you have very little on the drive), or making an image from one drive to another (meaning you'll need a USB to NVMe adapter to hold one drive while imaging it).  Macrium Reflect has a free edition that can do the job. You WILL need to back up all your user data on external media if you choose the clean install -- everything on the drive will be lost.  
I have been told that the Windows 10 authorization code is part of the motherboard.  I want to do a completely clean install, after which I'll add back the few programs I need.  Is it enough to simply pop out the old SSD and replace with the new one, after which Windows would immediately start?  Or is it necessary to back up the old windows program on a 32gb flash drive?  I'll probably do that anyways as a safety issue, but once done, would there be any reason to insert the flash drive to boot into Windows?
Replacing SSD with New Samsung SSD980 in XPS 13, i5, 2019