Any oil based polyurethane finish will darken/amber or give a yellowish color to the wood. Most clear exterior finishes are oil based. And no topcoat clear finish, even if it is exterior, will stand up to UV rays of direct sunlight. After a year or two those finishes will crack, bubble and eventually peel.
Assuming your wainscoting and the sequoia will be indoors, I recommend General Finish water based (semi-gloss) for a nice finish that preserves the color of the wood. I also like General Finish because it goes on great with a paint gun.
Osmo PolyX #3043 (clear satin) is a wax/oil type finish that penetrates into the wood. Since it does not sit on top of the wood like topcoats do, it gives a more natural finish and you will not notice a color change to the wood.
Here is a link to an old chair that I finished with Osmo PolyX #3043. Scroll down through the thread to see photos of the chair after finishing with Osmo PolyX.
I am restoring a surplus U.S. Navy chair that was manufactured in 1943 by the W. H. Gunlocke Chair Company. There are two U.S. Navy tags on the back of the chair The 13th Naval District was formed in 1903 and headquartered in the Puget Sound Navy Yard (Bremerton, WA). Headquarters were...
Curious, why are you going to cover the sequoia with clear epoxy?