I used large cotton towels on my last car and they kept the sandstone/beige seats spotless. Washed them occasionally and they lasted 14 years. Used a bit of Velcro at the top behind the headrests to attach each side together, worked well.
Have the same for Mazda to match the paint rather than horrible black to match the trim. Terrible colour, black for trim and the material they use for seats is not very good either, hence thick towels.