We are twins, buddy! Check out
my log.
Looking forward to your progress!
I would advise starting with the bar, but add weight
each set your first day until you start to struggle with it (stops being easy - technique falters a bit, or the speed slows down). That means it's a stimulating weight for you (to drive the strength adaptation); and as it's not objectively heavy, you will recover by the next session. Technique practice is part of what the warm-up sets are for; I'd hate for you to waste time taking a week or two to get up to actual stimulating weight.
What is your waist circumference? Any idea how much you are eating? The advice around here is 1.0g/lb bodyweight in protein, match that (or more) in carbs, keep fat low (below 100g). If gaining weight and fat (waist circumference), dial back the fat in 10g increments. If weight stays the same (with no increase to waist circumference), add more carbs if your lifts are struggling. Don't worry about a weight increase, especially if your lifts are going up, as long as your waist circumference isn't growing out of control (in which case drop fat 10g but add 10g protein or 20g carbs).
Is incline walking on a treadmill something you do now, and wouldn't actually consider exercise? Reason I ask - you don't need extra stimulus right now; but if it's very low-level (like, doesn't break a sweat, barely elevated pulse, no shortness of breath) and you find it restorative, sure. As for abs: the squat, press, and deadlift provide plenty of stimulus, trust us.