Just my experiences. I do not mean to offend anyone.
I have carried for a long time, going back to the 80's. Back then, AMT's 380 Backp was popular. I still have 2 in the safe. Those things weighed 18 ounces and pounded your hand. (I can shoot magnum revolvers just fine.) Its competition was Walther and Bersa 380s. Today, we have 9mm pistols lighter and smaller than those 380s.
Today, I have 3 Kel Tec P3ATs in 380 and 3 Ruger LCPs. These 380s are tiny and light. They are much smaller than my Kahr PM9. To me, it seems that even the smallest 9mms are noticeably biggeervand heavier than the tiny 380s.
I am not a bigger guy. Clothes for a guy 6'3" and 275# are very different than those for a guy 5'7" and 150-170# The pockets are very different in size. For me, sticking one of my G27s or the PM9 into a back pocket is not easy.
I do think the G42 and G43 are both great guns. The G42 is a real pleasure to shoot. However, both are bigger than what already have. Still, that G42 is a great shooter.
I have guns for different roles. I have some for the back pocket, bail out bag, vest/coat pockets, and for carrying on the waist. Some people like one gun for everything. Many people love the G19/23. I am the opposite. I prefer more guns, each for a focused purpose. It is different taste for different people.
A big point for the G42 and G43 are that they are Glocks. Not only are they good, but they have that same design as the other half dozen or more Glocks that most of us have. Familiarity goes a long way.