I think it’s recognition as an equal being on equal footing worthy of equal respect, not as an object of domination. In that equality the master can recognise themselves unalienated, and see themselves as a person worthy of respect in their own right. What worth is the respect gained from a slave who you dominate mentally and physically? It’s an incomplete recognition in its own right that doesn’t see the master as the full human they are as well.

Losurdo’s “Class Struggle” talks a lot about the multiplicity of class struggles through this lense.

Happy to be corrected on the above by any Hegel pros.