Kitchener stitch - how to start

I’m trying to join together 2 halves of a shrug with kitchener stitch. My question is: Should I finish off the ending piece of yarn that I just finished knitting with by cutting it and weaving it in. Then use a fresh ball of yarn to start the kitchener stitch with? thanks for any help - ktdsign

I use the working yarn.
I break it off, leaving enough length for the weaving, and thread the end through the needle.

Honestly, I don’t know if that’s how an “expert” would finish a garment. I always try to avoid loose ends.

I use the yarn that’s already attached.

I use both, using the active end to join them and weave in the short/cut piece as I’m joining them. This will be a tad thicker until the cut end is gone but weaving in later will do the same thing.