re: Is hitting muscle groups once per week enough?

If you start with the same lifts and follow them in order every time, you will be gassed later on each body part.

Mix up. If you start with this order: ABCD in one workout, go with BCDA order the next.

Or just do what I do. One lift per body part and rotate them every month of so.

Flat Bench or Incline
Back Squat or Front Squat
Regular Deadlift or Sumo Deadlift
Standing Strict Presses or Seated DB presses

etc

I’m doing other things during the week so this is more than sufficient for me.