I am not aware of any XL bands made by Apple for a 40mm watch, and only very few colors (like black) in XL for a 44mm watch.
You may need to search third party bands.
Unfortunately, many third party bands look good online, but not so good in reality. If it costs a lot less than an Apple band, I suggest pass.
You can also buy lug adapter connectors so you can attach any standard watch strap. Haven’t tried them myself, though.