Painting over existing textured backsplash?
After a thorough cleaning, you can paint with a roller that is designed for textured surfaces.
Not sure exactly what your question is. Over what kind of existing backsplash?
It depends on what your backsplash is made of - wood, plaster, sheetrock, etc. You can paint all of them, just be sure to do the prep work and use the right type of paint for the surface.
Are you asking about a tile backsplash? Could you possibly post a photograph to better see your situation and area of concern?
Having a visual might be helpful to be able to offer the best guidance .....to a help find the best suggestions or potential solution for your problem.
Here's a post that might help - https://brepurposed.porch.com/2017/09/21/paint-tile-backsplash/
Hello Jules1fly, hope this video helps you some
You may not have to paint! This can be applied directly over existing backsplashes: https://bachelorettepadflip.com/2014/03/03/diy-kitchen-backsplash-tutorial/