Going one step further: do not guess my regional preferences from my language. I want to have an American English UI but use little-endian dates, whitespace and comma as thousands and decimal separators, ISO week numbers in calendars (with Monday being the first day of the week), and metric units. I want English subtitles, but not ones meant for the hearing impaired.
Mmm... understandable, but less trivial to implement than the OP. What you're requesting is quite a lot of localization customization. Reasonable to expect this from say, Google Sheets, but you might be out of luck with apps with smaller budgets.
