The G19x and G45 suit me well. We are all built differently. So many firearms just don’t work so well, for me, so, when something does work for me, I will appreciate it. Each of us should find what works, for us.
My personal thoughts/factors/reasons:
1. I learned, long ago, that if I can conceal a G19, with a specific holster type and cover garment, I can generally conceal a G17 in the same place. My concealment nemesis, with blocky Glocks, has always been the outer rear corner of the slide. On a practical level, the shorter grip of the G19 provides me with no concealment advantage.
2. I have always shot G17-sized pistols better than G19-sized pistols. Even though I can get all of my skinny fingers onto a G19, the longer backstrap, and backstrap shape, of the G17/G19x/G45 just works better in my long hands. I believe that the grip making contact with the “heel bone” area, of my long hand, adds stability. A G19 grip is just a bit too short. This stability may not matter so much, for the first shot, but does matter when firing subsequent shots, at speed, as recovery, from each shot, is so very important.
3. As arthritis gets worse, in my right thumb, hand, and wrist, any handgun with a grip too short to reach the “heel bone” area of my hand, will cause damage, if fired with duty/service-level ammo. Actual, visible injury, not just pain. I traded-away three G19 pistols, in 2020, replacing them with more-“orthopedic” weapons.
4. A shorter slide/barrel are better, for me, when carrying IWB. I have a short torso and long arms, and, my shoulders are not getting younger, so, a weapon that clears the mouth of the holster, sooner, is an advantage.