I'm personally not a big fan of hybrid holster (which alien holsters are) after using a hybrid for a while the backing material can get worn out and can cause fitment issues and most do not have 100% coverage on their trigger guard. Full Kydex on the other hand remain stiff and rigid.
Renisance has been making quality full kydex holsters for Arex for awhile they have OWB, and IWB in several configurations they have full trigger guards good positive retention, and adjustable cant and their prices are pretty fair too.
Big Johnson guns N gear did a review of them in youtube here
https://youtu.be/aPrNWl2GTQw
And here is their site to look at their products
http://renaissancefirearms.com/

Robert, I mostly use Alien Gear holsters : https://aliengearholsters.com/holsters/arex-rex-zero-1-compact.html --------------- https://muddyrivertactical.com/product/arex-rex-zero-1s-9mm-iwb-kydex-holster/