Looking to replace front/rear springs

I have a Rough Country 3" lift and 31" all-terrain tires on my '98. Upgraded shocks to Bilsteins, and installed rear brackets to adjust the rear hangers to be 45deg at weight. Currently, on road driving is quite rough. It got better after relocating the rear shackles but that quickly faded as my rear leaf springs are beginning to sag heavily (rear is add-a-leaf). The front coil springs came with the lift kit, and I'm beginning to think they're too stiff.
I'm looking to replace both coil springs and leaf springs to give me a better ride on-road. Not to interested in completely replacing the kit. Any suggestions?

I am happy with my OME (Old Man Emu) leaf springs.

Give DPG Offroad a call and ask for their recommendations.

Which Bilsteins ? What is your tire pressure ?

Bilsteins have always been a firmer riding shock in my experience.

Shocks and tires are part of the equation. I do have Bilstein 1500. There's firm, then there's 1500's. The KYB Monomax are not far behind. With the Falken Wild Peaks, on road is not to bad. Still, firm or a bit more for the Bili 1500's
As to a 3-3 -1/2 rear spring. I did go with the OME. They are a dual rate spring. The are a bit higher priced than other springs. Also, you need to install the bushings. I used MOPAR, probably Clevite. The rear bushing went easy. The front, larger one took a bit of doing. Once in and straight, they slide right in.
A few others I looked at and considered, Zone lower cost. RE, note usually for quality. IRO, I've had good luck or experience with their products. Reviews seem good with them. They are a bit different length. So, need their boomerang shackle or the adjustable bracket.
I was going to delift from 4-1/2 down to 3-1/2 at that time. The RC springs and ProComps were a bit tippy for me. The RC springs gave at least a 6 inch lift initially. It took a few years for them to settle to 4.5. Holding that way. The ones I have don't have the friction pads. I hear the new ones do.
I did install the OME spring, but just as a roller. I needed to use some IRO boomerang shackles and the longest holes to get them on. Not an issue with your adjustable bracket.
As an aside, I do have Crown Up Country springs for my 2" lift. Those large bushings were a pain to get in. I had to use a makeshift spreader and still wasn't easy. That was with Crown bushings. The one from NAPA was larger OD.
Not sure on front springs.

Too bad your not in SoCal, I have some OME spring brand new that I need to get rid of.
With shipping being ridiculous calling Dirk @DPG would be the best option if you go with OME.