Here are a few ideas on how: https://www.bobvila.com/articles/painted-plywood-floors/
Is this a subfloor? Is this a powder room? I'm not sure if I would paint a plywood floor in a bathroom due to the bath/shower and any water that could spill over. Even with a toilet, there might be water trouble. Not to be a downer, I just forsee problems that you will hate.
However, you would have to seal it VERY well after painting. Multiple coats of a sealer or some sort of marine varnish.
I am looking for an easy way to cover an RV bathroom floor that the previous linoleum has split due to the harsh temperatures.
check this pin https://www.pinterest.com/pin/43699058872443045/
I guy I know used Home Depot deck resurfacing paint in a work van. This is heavy construction and that has stood up well to all the use. That should provide some grip and durability.
If you are covering an RV bathroom floor can you use peel and stick tiles? They are inexpensive and might work well in that smaller area. If there are any ridges from the previous floor that are sticking up you could sand smooth. Perhaps you already took that floor out?
Here are a few ways
Clean with TSP. Prime with Kilz or Bullseye. Then paint with a roller on a stick (like you would a ceiling) and cut in with a brush.