The solid fork I listed above in post 3 is a suspension corrected fork. But as I noted in that post you should measure the fork rake or offset on yours and also the axle to crown race on yours, as a replacement fork should have similar dimensions. And as I noted above, a bike shop might be needed to install the headset bearing race. I forgot to mention in the previous post, that you likely need to cut the steerer tube and would need to buy a star nut.
I did not look up your bike, thus do not know how wide a tire it will take. Wider tires give you more cushion.
Some people use suspension seatposts, suspension stems. I have never gotten much advantage with a suspension seatpost. A suspension stem, I have never tried one. But I have ridden on some really rough 4X4 roads on bike tours with a solid frame and solid fork, only using wider tires for cushioning.
There were times on this road that the washboarding was so bad I had trouble going over 8 km/hr, and that was with 57mm wide tires, but I do not think suspension fork would have solved that.
This road was pretty rough too.
That said, I understand the desire to have a bike that can take the worst of the surfaces you will ever ride on. But realistically a fat bike would be best on some of this stuff, but that fat bike would be a poor bike for your sections with pavement or tarmac.
This was another rough road on that trip. Tires are 57mm wide. I could have used a suspension fork, I have a RockShox fork that I have used on that frame, but when I considered how much of that trip was on pavement, the solid fork was the best choice.
Keep in mind your bike is 18 years old.
How much do you want to invest in it to keep it going compared to buying new?