The boards I can see in the kitchen are aligned with the other downstairs floorboards (i.e. not diagonal) and have zero visible gaps. There may well be asbestos in the mastic under the sheet goods, though.

What region of the US are you in? In the midwest, many 1920s area homes have oak in the living spaces and maple in the kitchen. You may be able to see if there is viable flooring if you have any built ins and remove the bottom drawer, or otherwise take up the fridge and have a good look. You can check out EPA guidelines for asbestos or search on this forum, it seems there are a couple schools of thought on dealing with it.

https://www.epa.gov/asbestos/protect-your-family-exposures-asbestos

We have a similar situation in our 1896 home. The underfloor is 2 1/4" pine that was refinished over 40 years ago (in the 80's) with a rough buff/new poly in 2001. As you can see in the photo we do have some wide spacing between a few of the boards and some damaged areas. We do have a finished basement below, so that helps with the heating/cooling. I will say that it has held up very well with an active household of kids, and multiple dogs, but it does have patina :) As we are looking at redoing the kitchen, we plan on replacing some of the boards that are damaged, but will leave most of it intact.

@kats737 we are in Massachusetts.

Unfortunately it is hard to see much of the mystery flooring - there are several layers of sheet flooring, and then laminate click, over it everywhere . i know there will be repairs needed since i can see from the basement that two ”gravity” heat system air returns used to exist and were patched up at some point.

And yes, there is likely some asbestos in the mix somewhere, given the number of layers, most put down before about 1950.

@kiniyagirl that looks nice! i am a fan of patina, and our house certainly has plenty of it elsewhere, so some patches dont scare me.