How to force English number format for all number values in a column?

This is what I see by default in my table:

All except 0.5 are aligned as numbers to the right. 0.5 is treated as string.

I tried various number formats, but none are willing to accept that 0.5 is a number, not willing to display . as the decimal separator. Instead, I see stuff like this:

Format:#.##0

The document is set to Czech language and changing the locale will break other things. I need this column in particular to act as if the language is English.