You already have 43mm tires running really low for your weight, a carbon fork(i assume), and a suspension stem. If you want even more suspension/vibration damping, then you could either go to an air suspension fork or get a quality handbuilt steel fork.
- an air suspension fork will give you the most suspension and vibration damping possible. Itll also be expensive and heavy.
- a quality handbuilt steel fork will flex more than your current carbon fork(i assume) and still be plenty stiff enough to do anything you want. It will not hold you back in any way, despite popular internet claims that an uber stiff 15mm thru axle carbon fork is needed on gravel bikes now. A quality handbuilt steel fork will give you the proper rake and trail to ensure the easiest possible setup for rolling over the road vs bouncing down it, and it will flex more for comfort.
Where do you ride that requires even more suspension?