Full Body vs Split
 

Title pretty much sums it up. But, here's what I'm thinking, and why I'm asking:

8 years ago I lost 70+ pounds eating ketogenic and doing a 5-day split, so I have experience with splits and I quite enjoy doing something new each day. That being said, after regaining 90 of that 70, I'm finally back into it with full force and 42 re-lost. I want to get back into a routine, but my body is nowhere near where it was when I was hitting the racks.

Should I follow the conventional wisdom on weight training and start with a 3x full body workout until I build my strength back up a bit? Or, is it alright to go ahead and start on a 3-day split? Eventually I'd like to get back to a 5-day split.

I'd go with the full-body 3x for starters.
It will depend on how hard you want to work and your body's recovery where the gains happen. If you work really hard you will want more days in between with no strength training. If you work more lightly each day, then maybe your body can recover.

If you split things up to let the muscle groups rest, there are whole-body hormonal effects that happen every day, and that can slow down the gains. Those 5 day splits work best for young males, for a while, then the big guys start leaving 4-5 days between sessions when the going gets big.

since you like something new each day, have you looked into a 3x per week for the strength training, and for the days off from lifting, other kinds of movement? like mobility, agility, play?

A fellow LCHF researcher had told me that he does a 3x full body and does his cardio on off days, just lifting every other day. I've always gone hardcore, work everything to exhaustion, etc... but that's one of the perks of a split (be it 3 or 5 day). you may be lifting almost every day, but each muscle group gets a full week to rest. Example, if I do a full body then I am working all muscle groups every other day instead of 7 days of rest.