You should no longer give advice.
When the fuck do you work your arms with a deadlift? Do you curl it at the end? Where the hell do people keep coming up with this.. I see it all the time now. If you bend your arms during a heavy deadlift.. you will rip something that shouldn't be ripped. You will increase grip strength with your deads, but you arms will NOT grow from this movement.
Core is definitely for stability, but I've learned over the years you can't take away crunches... they are still needed.
OP - get stronger. If your chest and arms are lacking, get them stronger. Don't worry about your "gut" until you are happy with your development. Hit your arms with compound movements AND isolation movements. Figure out if your upper body responds better to twice/week or three times/week.
What are your lifts right now?