I drive a sports car, a muscle car, a truck, another truck, a jeep, a 54 Chevy @ times, a 28 chevy @ times, a 2 ton truck, a tractor, fly different airplanes, and ride 2 different motorcycles. I can also drive a 18 wheeler, a combine, etc. as well.
Gee, I can handle more than one.... and I've never mistaken which one I'm in for another one. And, I seem to have no issues getting out of my car and go fly an airplane, or jump on my motorcycle. Or, messing up because I forgot whether it was an automatic or a stick shift on the column (54) or the floor (truck, tractor, 2 ton truck, etc) or how many gears the one I was in had, nor the shifting pattern.
So, why would anyone think, I can't handle carrying one gun today and a different one tomorrow ?? A revolver today, a semi tormorrow, a KAHR vs an XD because I'm wearing certain types of clothes one day and something different the next ?
If you can't pick up one gun vs another, and you can't go to the range without shooting more than one gun without getting confused.... then stick with one EDC gun and stick with it. But, if you are practicing with them, it should not be an issue switching from one to another.
I may carry a semi with a revolver back up , or a revolver with a semi back up..... I've never been confused about which gun was where, nor how to use them, even under high stress and being shot at.