It's just wool felt, cutting it would be fine. You just lose out on the rounded corners.

You can make one yourself. https://www.joann.com/35pct-wool-felt-36in-w/8020349.html (Smoke)

Wrap that around this: https://www.michaels.com/3mm-thick-flipside-cork-roll/D083440S.html

With some spray adhesive and you have a nice wool mat for a fraction of the cost.

Or if you absolutely NEED the high grade Merino wool: https://www.thefeltpod.com/3mm_wool_felt_fabric_s/1856.htm It even comes in a wide variety of colors.