If you’re new, IMHO you should be looking at the distro as a whole, not the DE specifically. Yeah, if you find one you mostly like but want to try other similar distros, it’s probably a good thing to stay with the same DE. However, it’s not something to get hung up on as distros often tweak the DE.
And to answer your question, Cinnamon. After years of distro-hopping, I’ve spent most of the past decade on Linux Mint.
Replacing an SSD is pretty simple on Linux; just copy over the data, adjust the partitions, select the new drive in UEFI/BIOS. If you want to try a different distro, any time is good, but a new SSD doesn’t require a reinstall.
My advice from my distro-hopping days is to dual-boot with potential new distros (unless space is at a premium). I just made sure to share important folders like /home/. That way, if I didn’t like my new setup, I could quickly fall-back to the old.