@Scoutbob , if you value a non Glock person opinion… here you have my 2 cents.
I’ve been trying to have a better relationship with G Family recently and I’ve been focusing on both models: G19, G45.
I shot them almost side by side (one day difference) at the same Range, using the same targets.
First of all - both handguns suck OK… I’m kidding, They just sits bad in my hand I cannot shoot them accurately.
But, regarding your question. I personally felt better with G19. The grip length was perfect for my hand and all 3 fingers got good support.
G45 (I assume this also would apply to G19X) stuck out too much and actually it bothered me be during shooting.
Did that deference affected my shootability? Somehow yes. Even my shooting was bad with both I got more pleasure with shooting G19.
But I think everything is about which model sits better in hands.
If you are OK with G19X you may be good with G45.
Just remember - G19X is just a bit heavier and slimmer than G45. It can be either good or bad for you