can you work around this by copy/pasting maybe all 25 characters at once or maybe each segment at a time?
alternative: install somewhere else (windows pc or VM) and copy the install dir contents and registry
alternative 2: get the steam version, I just tried it with proton experimental and it seems to work fine.
edit: steam lets me choose the base game, war chiefs or asian dynasties, AD and WC work without a problem but the base game asks for a key and I can also just input 4 characters instead of 5. but I’d always play with all expansions https://feddit.de/pictrs/image/d80dd45e-2194-4c78-a7a7-9579d8c3af0f.png