I had this exact same repair. Whirlpool right?

You can get the entire lower plastic piece online. I think even amazon. There is an option to upgrade to stainless steel bolts rather than clips which I recommend. Use the part number to find it on amazon. Was not expensive.

The plastic piece is held on by vertical clips. One in front and one in the back. it takes a bit but all you need is a flat head. I believe there is a YouTube tutorial with the parts. I'll edit the comment if I find the link. It took maybe 1 hour to do both sides.

EDIT: https://www.amazon.com/gp/product/B088TB7Z6D/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

There are two size wheels so make sure you get the correct ones.

Instructions: https://www.youtube.com/watch?v=AOC0hILjwxM