There is definitely an issue with keeping certain things in stock on the GF site and it was there before the pandemic (obviously it’s exacerbated now).
There are a million other places to buy acrylic, so if you’re ever in need of that, browse the forum and you’ll find lots of options.
I would definitely try to find a backup source for whatever wood/ply you use if you rely on it for business. I would do that with any material I require, but in this case, you’re relying on a small specialty supplier who has fluctuating supply and demand. You might have to finish the wood yourself, but at least you won’t find yourself stuck for orders. It’s more work, but it should actually be less expensive, so hopefully it all balances out!