Is it possible to change Siri’s English speaking dialect without compromising functionality?

I would like to use Siri with a British dialect for reading back classics. After researching numerous forums on this, including Apple, I found that people are doing this (many on Reddit for example) with no problems. However, I discovered that if I used a different dialect, the accessibility read-back wouldn’t function at all. I thought it was a glitch in the read-back. However, when I changed it to American Siri, it worked perfectly. I personally have not found an American Siri voice that is not irritating and meets my needs. As I say, many indicate they are using English speaking alternate dialects without a problem. Is there a way to work around this? Isn’t rocket science! I would be much appreciative if anyone has any knowledge of this particular situation. Thank you!