Mustafizur only bowled off cutter (I had only seen him bowl leg cutter once in test, and you know, more than half of his back of the hand deliveries ended up as a beamer). That was not the case with Barnes, who could swing and seam the ball, before it became a thing.
And even if they were similar in attribute, that wouldn't mean they would be similar in outcome. I could argue Bumrah and Naveen Ul Haq have similar actions, doesn't mean if Naveen fails in tests, so should Bumrah.
And as I've said this earlier, if cricket exists after 100 more years, the game is gonna evolve even more. Would you then agree if someone says, "Sachin's stats can't be taken at face value, as he performed against limited opponent and in a very different time"?
as Red_ink_squid said, we should compare players by "player vs contemporaries" vs "player vs contemporaries" and Barnes was the most dominant bowler in his time by a long shot.