I can give you lots of options. Bilstein 4600 shocks on all four corners is an easy and inexpensive way to reduce some harshness. They provide modest ride improvement.
Sulastic shackles is another relatively inexpensive fix and provides a noticeable improvement but not on deep suspension strikes. I have them in addition to the Bilstein 4600s.
I’ve also added a Bilstein 5100 steering stabilizer. Huge improvement in front end control in all conditions but doesn’t really improve ride. I can absolutely promise you that you’ll not regret upgrading the stabilizer on an F350. Cheap, 15 minute job, and dramatic improvement.
Your front anti sway bar, if you have one from Ford, is contributing to front harshness. A quality replacement will improve the front end feel. This is probably the best thing any of us Ford SD owners can do to improve front end road feel. I’m still looking into which one is best and am considering another option I’ll share later in the response here. Easy DIY by the way.
Progressive coil springs up front are not terribly expensive but will improve ride quality.
Progressive leaf springs are anywhere from 600 to 2k dollars. But, they’ll improve your ride significantly. Have to watch your load ratings though.
You can also look at mini-packs. They usually replace overload springs and are essentially progressive emulators. They work but not as dramatically as progressive packs.
I may be going with this option below in 2026 if I get a windfall I’m expecting. But it’s 10 grand. I won’t lift it at all.
Icon Vehicle Dynamics is another great company. You can talk to them about options. They’ll set you up with a great kit but it will more expensive than just the Bilstein option.
Finally, Carli Suspension is extremely popular but again pricey.
Lots of options. I’ll take whatever criticism folks have on how much I spend on suspension rebuilds!. It’s not for everyone but is my thing. I even have custom built suspension on the scooters and every motorcycle we have ever owned.