Is it OK to have a 1yo cat shut in a room for most of the day for re-introduction? Any tips?

We properly introduced our 1yo cat to our other two cats like 6 months ago, but then she got spayed and when she got back from the vet one of the other cats just hated her. She’s very aggressive towards the 1yo and they tussle often. So now we are going to re-introduce them.

This means 1yo cat will go back to being shut in a room the entire 8 hours we’re at work. She hated this the first time we did it and yowled incessantly to get out. She’d climb the door and walls and scratch the carpet. We made sure she has everything she needs, water, litter box, toys, bed and we go in there to keep her company regularly. But she still hates it.

Is this still an OK thing to do with a cat? I know it will benefit everyone’s well-being but it just feels so wrong and cruel.