Adicionar:
builder.Services.AddLocalization();
Configurar:
var supportedCultures = new[] { "pt-BR", "en-US", "it", "zh-CN" };
var localizationOptions = new RequestLocalizationOptions()
.SetDefaultCulture(supportedCultures[0])
.AddSupportedCultures(supportedCultures)
.AddSupportedUICultures(supportedCultures);
app.UseRequestLocalization(localizationOptions);```