Transplant advice

I have this Fall Phlox growing out of a crevice between my home and the patio. I want to move it to a location where it can thrive. I’ve never dug up any plant let alone one from such a delicate/snug location.
I’m thinking I may need some root stimulator. Also maybe best to put in a pot until it gets a bit more hearty.

Any advice for a successful transplant?

I’m in a 7b zone.