In The Gentlemen, Matthew McConaughey plays a British drug dealer that operates his business in Great Britain. All other characters in this movie, including his wife, his enemies, his henchmen speak English with British accents, except for an American business man, played by Jeremy Strong.
It is customary for an actor or actress to speak English with an accent that matches this character's background, for example, Mel Gibson as William Wallace in Braveheart.
And for an actor such as Matthew McConaughey, who was willing to lose so much weight in Dallas Buyers' Club, I cannot see why he would not be willing to speak English with a British accent to be more aligned with the character he played in The Gentleman.
Am I missing something from this movie? Or is there a reason why he does not do it?