If you post your exact workout then I can tell you how much it sucks and what you should do instead...
just kidding. Honestly, besides echoing what the others have said I Would encourage you to think about a simple fullbody for now or maybe and upper lower split. but whatever you are doing, I think at this point just getting back into it every workout should pretty much result in some progression past the last workout, at least for a while. If you're not keeping a logbook you need to do that.
But being someone who's stopped and then returned to it later and from what I've seen one mistake people make is starting out too heavy, maybe too close to maximal loads. While you may be very strong your bodies ability to recover is not what it once was. I.E. you call yourself a newbie but you did do it before, so maybe deep down inside you don't want to feel like a newbie.
For instance, you mentioned the word "intensity". Whatever your definition, the first word you should be worried about is "progression" or simply progress. Progress is how you ARRIVE at intensity. You may simply need to scale back the weights and or volume and give your body a chance to adapt. At this point you should probably making progress on a workout to workout basis. But whether it's weekly progress or it's monthly progress that is the key and you have to figure out how to do that. Because adding in a bunch of extra sets on THIS workout, only to fall back or regress on the NEXT workout, is going to become wheel spinning.
It seems like every day I read someone saying they don't have enough energy to finish their workouts. Usually they are looking for a supplement (which can be useful) but lack of energy could also mean the presense of FATIGUE. It seems to never occur to anyone
. (I'm not saying you have to be fully recovered to workout or any of that nonsense, btw).
Course many times these problems are behavioural, so if you're not getting proper diet and rest, then all bets are off.
Sorry for the long post
.