Quickly, my answer is Epoxy, but to your point, there is wood movement to contend with, so the answer is not that simple. I guess my point is that epoxy is not a single product, and you might look into those epoxies more dedicated to finish than to adhesive applications.
My first attempt at Epoxy finish was with Bar Top, which is very viscus, and although trying to follow the instructions, I found that there is a lot of lore around it. First and foremost, mix the product well, then mix some more. In my case, wood movement would not have been an issue since it never setup completely. That's on me, not the product.
Once I cleared out my issues, that product is fantastic when you lay an initial thin (not viscosity, but rather depth) layer, working out the bubbles (with a heat gun) that will surely appear. The second layer tends to be the thick "Bar top" layer. That bar top, veneer over substrate, was solid for the three years I had the house.
Another product that I'm not sure is still available is a "water thin" two part that I found at James Town (http://jamestowndistributors.com/). Fine Woodworking did a study on longevity and found that this epoxy would not only "cure" punky wood, but for a door subject to weather, it provided a strong flexible base to any other finish such as Spar Varnish. I still keep what I have as a two part, and when I have to get a good finish on questionable wood (and Cedar tends to fall into that bucket) it is what I reach for. In my mind, you can decide to sand, reapply, sand, etc. or in my door's case, apply the epoxy, set, then sand and use your favorite varnish or other finish.
James Town now refers to https://www.jamestowndistributors.com/userportal/show_product.do?pid=97636 or "Penetrating Epoxy" I have not tried this replacement.
I know the other products out there can be inflexible once cured, but I've yet to see a failure with the Penetrating base.
Good luck, and know nothing is absolute here.