It’s not what I was asking. G19x has G17 frame and G34 has G17 frame. The question what Gen it needs to be for working on G19X?
I answered your question.
The G19X DOES NOT have a G17 frame. It has a G17 GRIP LENGTH, but the forward part of the frame, where the light mount is, and that I show in the pics above, is G19 in all dimensions, INCLUDING length.
The G19X has a bastardized frame that has dimensions of the G17 AND G19 in it.
You can’t mix Gen3/4 uppers and lowers with Gen5. G19X is Gen5.
If you put a G17 slide assembly on a G19X frame, it will work, but you will have the large gap that I show above, with an exposed guide rod/recoil spring.
A G34 slide assembly is even longer than the G17, so it would be even worse. I have both a Gen5 G19 and G34 at home, so if you’d like, I can mock up what that abomination would look it in regards to exposed guide rod/recoil spring.