I think red oak is hard to do natural so IMO if you have to ask how to do this you probably should get some help. In your first piv the floors look to be 2 different ones is tah just lighting or really 2 different colors fo floor.

you might need to do test spots and then sand them down again after you choose one.

from my experience, any sealer will darken the wood a little, no matter what. water based seems to darken the least. you can get sealers with white pigment that slightly lighten, but also gives a very slight whitewashed feel (and for some wood types, appears a tad pinkish or greyish). it reminds me of the beachy look, which is trendy and will go out of style sooner or later. personally, I'd opt for clear and just allow the floors to be natural. it's classic.

but do some tests! decide for yourself what look you like.

here's a thread discussing light stains on red oak floors, it might help: https://www.houzz.com/discussions/4458616/light-stain-color-for-red-oak-floors

I am diy-ing our red oak as well. Dogs haven't handled the pandemic well . . . I assumed because of the doggles I would go with oil based stain and poly. BUT turns out Bona products are used by a number of NBA teams -- and I want sports floor tough. So we are going with Bona Traffic HD. Not sure about a sealer yet . . .

I want to bleach my red oak floors so bad! But no flooring guy wants to go down that road! So I’m to the point that I might do it myself. I have done a TONE of reading up on it and I have even purchased a 28% peroxide & lye delusion solution (same as the 2 part A&B floor bleaching solution they sell for wood floors but at half the price). So PLEASE tell me what you used , how may times did u do it and what advice do u have ? Thanks!!