The best thing I ever found was CPAP strap covers on Amazon. They're just a length of padded material that you wrap around headgear and fasten with velcro. For me, it was mostly to prevent the lines on my face that my headgear left in the morning. I just throw them in the laundry every so often and let them air dry. I'll try posting a link.

https://www.amazon.com/gp/product/B08598N6S8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I bought these. They work great.