I think the whitewash looks lovely :)

I like the whitewash too!

I don't care for the whitewash. Given the high contrast between the stained & unstained areas, I have my doubts as to how successfully whitewash will disguise the problem.

So I I would weigh up a choice between painting the t & g or adding a second layer or some kind of wood treatment over it, if possible structurally.

The beams can likely be blasted or sanded to restore them to a natural color.

it has been suggested that we add a hint of grey and then a much thinner white wash layer. I am not needing to hide all the damage btw. Much more concerned about getting the smoke particles out. That's a true health issue. This is an authentic midcentury modern --we've managed to preserve a lot of it and I don't want to keep chipping away at the history.

and btw, the beams were painted green in 1951, and we are restoring the color, but of course, blasting them first.

I would powerwash to fet rid of the particles but then clearcoat with Sikkins. It will make the wood beautiful again and the original color will be enhanced and look gorgeous with that green. we used it on our 1910 original stairway indoors and the basement stairs as well. There is no color added it just enhances the wood . Our basement treads were in terrible condition and they are breathtaking now.

stairway after:

basement before:

Basement after

https://www.google.com/search?q=Sikkins&rlz=1CDGOYI_enUS676US676&oq=Sikkins&aqs=chrome..69i57j0i10i131i433l2j0i10l3.24938j0j7&hl=en-US&sourceid=chrome-mobile&ie=UTF-8