I have select options list and trying to get transform on select and display transformed value as selected. when modify options list its display but not getting how to do without impacting list of options. Any help is very appreciate.

steps trying to achieve:

for example i have selected first option from list

-selected value show transformed as per Expected Result image (plus sign and countryCode value).expected result:+93

-ngValue should not impact.expected result: 93

-list of options should not show with transformed value. expected result: Afghanistan (+93)

here is the code example stackblitz

Current result: current select behavior

Expected Result expected result image

Thanks in advance.