`var ci = new CultureInfo("sv-SE") {DateTimeFormat = {ShortDatePattern = "yyyy-MM-dd"} };

        app.UseRequestLocalization(
            new RequestLocalizationOptions()
            {
                SupportedCultures = new List<CultureInfo> { ci },
                SupportedUICultures = new List<CultureInfo> { ci },
                DefaultRequestCulture = new RequestCulture(ci)
            });`

We have this in startup/configure to make sure that the culture is set to swedish in the UI. and it has worked up until we upgraded to .Net 5. Now I have to add NumberFormat = { NegativeSign="-" } to stop it from returning Ascii 8722 as the negative sign.