Sounds kinda like how I do floors... it takes forever.

I use a synthetic bristle brush and thin the poly to 50/50. the first
coat is really sparse and is absorbed by most of the white oak, then
apply another coat of 50% gloss poly / 50% thinner... starts to look
better.

Then sand with 400 grit paper, then put a final coat of about 30% poly
/70% thinner on top. This leaves a pretty good finish, but it takes
FOREVER to get rid of all the bubbles, and you've gotta use a very very
strong flashlight and put your cheek on the floor to see them.