Black Friday bumper leads to more spending

2003. North east. Both bumpers nicely rusted out. Truck has new frame.

So I pulled the trigger and got the relentless diy weld bumper kit, which got me thinking about the suspension. The xcab I have received a new frame last January so I assumed it got new shocks. The fronts look clean and stock but the rears are the blue and yellow Bilstein bodies and are pretty pitted with rust and showing age. I'm assuming that they were aftermarket and therefore didn't get swapped. My rear leafs are almost flat if not concave with minor loads so now I'm thinking the rears should be looked at. Woe to my wallet.

My questions are:

Are my assumptions about the shocks being aftermarket preventing them being swapped correct?

Does the relentless bumper really merit a suspension upgrade due to weight?

If I did go with a new suspension but don't go off-roading or wheeling what is the best ride for the money package? (2-3" lift and stiff suspension with HD springs would be a huge bonus.)

Edjakate me. Thanks.