Believe me when I tell you that the the Zagg Rugged Messenger is your best option for rugged cases for the 10.5" models. I had one on my 10.5" iPad Pro and it was my favorite case of all time. I loved it so much that it almost kept me from upgrading to the 11" iPad Pro.
https://www.bestbuy.com/site/zagg-r...ro-and-ipad-air-black/5829100.p?skuId=5829100
If there were a version of this case for the 3rd gen iPad Pro, I would have bought it the second it was available. Here are the reasons I like it:
1) Feels good and solid in the hand when completely assembled and folded up.
2) Offers full side protection for the iPad.
3) Has a fantastic keyboard with multiple backlight colors and media keys.
4) Several typing angles available due to a really good sliding magnet system on the back.
5) The part of the case that actually houses the iPad itself is held in to the spine by a magnet. Which means you can pull it completely out of the keyboard cover part of the case and use it like a standalone iPad while STILL HAVING FULL BACK AND SIDE PROTECTION. I often used it this way at night when I didn't have any work to do that involved typing.
6) The keyboard battery lasts forever on one charge. I think it was something like 2 years.
I really can't state enough how much I loved this case. When I sold my iPad Pro, I sold the Rugged Messenger as part of the package and I just really hated letting it go. Unfortunately, I think with the 3rd generation iPad Pros, most of the third party options for keyboard cases have gotten so much worse than they were in the 2nd generation. Zagg's offerings are especially bad. I feel like the Apple keyboard folio is pretty much the only option that I can live with at this point.