I found a video where they put small holes in the varnish with a knife, then let it sit wet for a couple of hours, then steam it through a towel, and it worked pretty well on a test dent!
The differences between dents and craters is that dents merely compress the wood, without damaging the fibers, while craters break and destroy fibers. Dents can be repairing by expanding the wood, but craters aren’t fixable.
You have to remove the varnish by sanding first, then try to iron the floor. There may be poor contact in the middle so try ironing the other edges.
Other than that, you are gonna have to get new boards installed.
I found a video where they put small holes in the varnish with a knife, then let it sit wet for a couple of hours, then steam it through a towel, and it worked pretty well on a test dent!
The differences between dents and craters is that dents merely compress the wood, without damaging the fibers, while craters break and destroy fibers. Dents can be repairing by expanding the wood, but craters aren’t fixable.
Yeah, OP wants to work over a large are, not just where the dents are.