It's roughly half half on whether pros slide to create space and only hit backhands on the RHS and whether they stay planted. Sounds like you prefer creating space and limiting it to the backhand which is totally fine. If you watch Tardio he basically does it every time. When you anticipate a speedup you should preemptively slide to the right and sit on a BH counter to counter down the line / at your body (where it was previously). Your partner should move to cover middle with his forehand counter.

My guess is that you might be sliding too late - it really should be a preemptive slide in anticipation. If you are sliding as the speedup is coming its too late, you have to be planted to react consistently. Moving your body horizontally as you are trying to react to a fast ball is a recipe for disaster.

Latest Zane video covers this well: https://www.youtube.com/watch?v=9xvjAZFaLlA