You are right.
We just don't stock acrylic. It's not in our wheelhouse currently.
Styrene does work fine temporarily outdoors. Our largest customer uses it for drive thru menu boards that they replace every 30-90 days. Will it last a year? Not really. Will it last a month or two? Yep. In the shade, you'll get even more life out of it.
Either way, I had hoped the bumps to the post would help the OP find what they are looking for.