It looks like it’s time for a freshen up coat. All in all, the wood is in great condition and I don’t see any reason to strip the coating and start over. It just needs recoating.
The galvanized strip above the one board is dripping down with dirt and that dirt has built up and become moldy. That should wash off with a strong solution of Earth Clean.
The other boards weathered a little too long (the light colored ones). I would sand these with 150 grit and then apply a good two coats of Mountain XT Clear 00.
That should bring it all back to life.
This kind of looks like Mahogany to me? Maybe a piece of ipe? Regardless, the wood grain appears to be nicely illuminated and I don’t know of any other way to keep those exotic hardwoods from turning grey.
1. Earth Clean
2. Sand 150 grit (lightly to scuff up surface and smooth it out)
3. Mountain XT Clear 00 x2 coats