There’s the “right” way and then there’s what’s practical. Here’s the “right” way:
Rough sand the entire floor to wood. Fill the voids with Starbond CA glue of the appropriate color, low viscosity for leveling. Fine sand the entire floor. Refinish with oil-based polyurathane.
If you know what you’re doing then this will take three days, most of it dry time. If you don’t know what you’re doing then one way or another you’ll destroy the floor during rough sanding.
Future fish food.