The m.2 drive is SATA and boot drives in your model are generally NVME which are much faster. And yes you could install an NVME M.2 drive and boot from it. Now as far as replacing the HDD with an SSD drive, that is the simplest upgrade and will boot fine. The Kingston SSD you listed will work fine as well. I usually tell users that are not tech comfortable that the 2.5" SSD is an easy upgrade and will be a huge upgrade from your HDD. The following video might help.
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