Intermediate Lifting - All Body or PPL Split

I'm a 42 year old guy in good shape (40 pushups with decent form for example). I've always gotten exercise and did 20 minute resistance sessions several times per week. After some muscle loss from a injury, I'm lifting much more intentionally. I started 45-60 minute lifting sessions a month ago 3 days per week, with some cardio built in after. After a lot of reading, I am trying a push, pull, leg split. Although, I'm finding to hit muscle groups twice per week, a day of this creeps into more of an all-body day.

My questions: 1) Should I be thinking of myself as a beginner or intermediate lifter? 2) Should I quit with the split and do all body 3-days per week? I could also do a Push/Pull, Legs, All-Body split? Or stick to PPL? 3) Is 5 lbs of muscle in a year a reasonable target? I'm already a toned guy with visible abs so I don't have extra pounds to shed.

Thanks team!