Full Body Vs Push Pull Legs

I'm a beginner, and this is my third week working out. I've been given a three-day full-body workout regime. I like it, but I find myself throwing random stuff in there to make it harder because I love feeling sore, but I also get tired.

I'm doing this for medical reasons, a lot of muscles are deactivated, so feeling muscle soreness in certain places is good for my mental health.

Im thinking of doing a Push/Pull/Legs split, but I'm only going to be working out 3 days a week, and I'm worried 1 day a week is not enough, even if I'm overworking the area on that certain day.

Thoughts?