My number one suggestion would be to get a JM Kydex AIWB with an RMR cut and for a 17 length (yes, not 19). Get it with the large foam wedge that can be taken off and on so its comfortable for both hip and appendix. The AIWB is my favorite holster I've ever owned. Amazing quality and design.
https://www.jmcustomkydex.com/p/AIWB.htmlRegarding comfort with appendix carry. It is a system where components cannot be overlooked. I'm convinced many that have tried appendix and didn't like it didn't have the right equipment/and or didn't know how to set it all up properly for their body. Spencer Keepers offers a class on just carrying appendix and its amazing how much you can learn just about this carry position.
1. Starting with a truly proper AIWB holster. I'd say 95% of holsters marketed for such are not close to correct. The right holster design conceals better and is more comfortable. It must have a vertical wedge and a horizontal cam.
2. Proper belt like an EDC Foundation. Not too stiff but properly mates with the horizontal cam on the holster. AND the buckle must be minimalist or it will protrude with a gun in this position. The EDC has the perfect buckle.
3. Boxers or compression underwear go a long way for comfort. I use Underarmour compression underwear and compression undershirt. These are a huge part of comfort because they make the pistol slide against the material, not dig and stick to your leg/belly.
Another great company is Tenicor. Their Velo 4 holster is a brilliant design for appendix which I also own. Their Certum is designed to work well for both appendix and hip. Plus - these automatically come cut for an RMR. All of Jeff Mau's gear is pressure tested in legit force on force training. He's really serious about innovative gear that works.
Good luck!