I did change my surname late in high school. Maybe it is cause of my country, bur yhat was not so easy. I just wrote a letter to the birth certificate register with a good reason to do so. Once they replied with “you’re good to go” I just wen to the passport issuer with that mail and changed my name. What happens next is the problem - change name in all instances - school, work, license, bank and so on.

When I was younger and less involved in this world, it was quick. Today, with all the subscriptions, payments and registrations - screw that. Too much effort.