Is it possible to have a English accent without being raised in England?

Answer 1

Not a true English accent, no.

However, with months of practice and patience, you can learn to pronounce words in a similar way as the English do. Bear in mind that there are actually several different dialects of the English accent. The one most heard in the media is the Central London accent.

Actors spend weeks, sometimes even months, practising a new accent for their roles in films. Sometimes with the help of a speech therapist. The English Actor Gary Oldman had to have speech therapy to recover his natural British accent after after playing so many American film roles in a row.
So it is certainly possible to learn to speak in an English accent. It is not as easy as most people think, trying to naturally speak a different way from the dialect they were brought up to speak.
However do bear in mind that there are pronunciations that some nationals have difficulty saying because of the way they were brought up. For example, Laura is pronounced "lore-rah", but some Americans tend to struggle with that and pronounce it "Lara", because they are told to drop the "u" in words. (The iconic English game figure, Lara Croft, was originally called Laura Croft. But once it became apparent that Americans were having trouble pronouncing her name, it was changed to Lara).

It is possible to learn to speak the English accent, but it will take a few months to master, because you were taught to speak and spell differently. Look for courses in dialects online or in your local area.