Use Dawn dish soap. It pretty much kills fleas on contact. The degreaser destroys the flea’s breathing membrane. It’s doesn’t get rid of the eggs though. The bigger issue is the fleas in the house that are not on the dog. They will be harder to get rid of. An egg can stay in a dry place for a very long time and when the conditions are right they hatch again.
Read an article where it stated flea powders effectiveness is where it gets dropped as part of the dogs routine of going between, under etc. items and to regularly vacuum. I’ve also heard that when you trim a new flea collar for a dog, to put the trimmed part in the vacuum bag to kill live fleas picked up.