It can be done, but it depends on budget and level of dyi experience (and patience).
Here is one link
Utube is another great source.
Good luck and post some before and after pictures when you're done. We'd love to see them.
They make tile paint . Look for it in Home Depot or Lowes. Also you can tile over tile.Use Eco Prim primer on top of tile. It makes a surface similar to cement and gives new mastic a coating that can now grip to. You then add new tile and grout.
Paint and possibly stencil it if that agrees with your design aesthetic.
You can paint over them. Start with a good bonding primer and be sure to seal whatever you do with several coats of water based polyurethane. I’d advise you to not tile over them as the new floor will fail, ruining both the old and new.