I switch regularly between German and US keyboard layout (due to different physical keyboards and also having to communicate in different languages).
It is terrible that ( and ) are on the 8 and 9 keys in German layout and on 9 and 0 on US. It frustrates me to no end (add in how IDEs will auto-complete parentheses and I'm constantly lost in a complex decision tree of how to recover from being one key off) and I can't seem to build muscle memory well like this. The other symbol keys are also a wash. Particular offenders are y and z, ? and -, " vs Ä vs @, as well as + (who came up with the idea of requiring shift for that?!).
I just can't intuitively keep up with what layout is active and/or how to adjust my typing, even if it's always the same for the same application. Frequently I settle for "try one thing and correct if necessary". Obviously slows me down a lot.
Can mostly offer my sympathy. Have the same problem with the Swedish layout. Especially the fact that all systems seems to have their own placement of the | character is quite hard on me.
At the moment I’m trying to handle it my learning to code in the se-layout. Isn’t looking promising though, don’t think I’ll ever get used to the {} (it’s a bit curious that the Mac has the Swedish letters printed on the keys but not the other symbols you need)
I think when I finally give up on this I’ll try a en layout that lets you type the required umlauts and rings by combining instead.
I have my keyboard set to UK Extended. It's able to do most diacritics, so I just stick to it even when typing German and other suitable languages, like French.
Umlauted vowels are done with AltGr+[ followed by the vowel. ß is done with AltGr+S. It's a tiny bit less ergonomic than having dedicated keys for these letters, but I consider the tradeoff worth it since the letters don't occur too frequently in German and I only need to memorize one keyboard layout.
I don't know if something similar is available for US layouts.
Of course there's only so much you can do if you're facing a (physical) US keyboard (as it lacks a key or two, compared to the German keyboard) but you could, at the very least, adjust its (virtual) layout so that it resembles the German one more closely. Of course this assumes that you're touch-typing and not looking at the keyboard because otherwise its labels might confuse you.
As for communicating in different languages, though, why do you feel the need to regularly switch between the German and US keyboard? IMO the German keyboard can do everything at least as well as the US one can (in terms of accents and so on), except for braces and brackets.
If the latter bother you (I know quite a few people who use the US keyboard for this reason): Why not adjust the second and/or third layer of your (German) keyboard layout and make braces and brackets more easily accessible? Same goes for any features that you might be missing.
A lot of people seem to be recommending switching to an entirely new (first-layer) layout while your issue could probably be fixed by:
1. changing the second and third layer
2. using that same layout everywhere, on both US and German keyboards.
Get yourself an US ISO keyboard or US keycaps and then set up a modifier key combination for special characters, it's best if you have some extra keys dedicated for macros though.
I had a similar problem (Spanish and English keyboard share the () problem, and we have ñ where ; usually is, but Spanish keyboards are qwerty and not azerty). I switched to the US-international keyboard layout and use that to write in any language now. I find it a good compromise, although it's not perfect neither to write in Spanish nor to program/write in English.
It is terrible that ( and ) are on the 8 and 9 keys in German layout and on 9 and 0 on US. It frustrates me to no end (add in how IDEs will auto-complete parentheses and I'm constantly lost in a complex decision tree of how to recover from being one key off) and I can't seem to build muscle memory well like this. The other symbol keys are also a wash. Particular offenders are y and z, ? and -, " vs Ä vs @, as well as + (who came up with the idea of requiring shift for that?!).
I just can't intuitively keep up with what layout is active and/or how to adjust my typing, even if it's always the same for the same application. Frequently I settle for "try one thing and correct if necessary". Obviously slows me down a lot.
Any suggestions welcome.