Try satin poly a lower sheen, But go to a real Paint store that has
different brands, sheen levels vary from manufacturers. P&L has a true
lower sheen satin, but many are really semi gloss , or try pints if
possible. Or get technical and ask for the sheen level, everything is
rated, but you wont get that info unless you research the tech data.
Look hard enough you might find flat poly. Poly can also be buffed down.
Talk to a real floor pro they know.