For the longest time I just used the CapsLock key as a layer switch, so there was no problem when using other computers. I did not change anything from the standard layout, but just added additional options. I now use my own layout and am not compatible anymore, but that is not needed IMO.
The mirrored key is the quote-key on an US layout. You will loose those, but gain the complete left side of the keyboard in exchange.
I do only use my own computers, so do not care if things do not work on someone else’s computer. But I used Autohotkey in the past to realize all functions on a standard keyboard and recently switched to Kanata (which Max recommended). So you can plug in your UHK to any computer and have the functions or create a Kanata config file which you can also run on your laptop or any computer.The latter is important to me, because I do not always have an external keyboard with me, when travelling.
EDIT (2024-08-30): Here my config ENDe - my final keyboard layout