Bridge auction and play with a 5521 hand opposite 1255
You could attack Diamonds before touching clubs, while the A♧ is still an entry to south. This sets up a long diamond, but it works only if the opp with short diamonds is also short in trump. On the actual lie, the long diamonds will be trumped. 

You don't mention it, but on your line a diamond must have been discarded on the second club trick so that the second diamond can be trumped. 

You also don't mention but in the 4-card ending when you hold ♤Tx ♡8x  in the north hand, (after the Diamond ruff) you must lead a spade so that the opponets will have to lead trump into your 8x. This works on the actual lie.

I don't see a celarly better line of play.

On bidding, I agree with the comment that you could stop in 3NT. But on the actual lie, i don't see a play for 9 tricks, with neither black suit breaking favorably.

And I don't see a good reason to try for slam over 3NT. It certainly doesn't work on the actual lie, but with no running suit and no more than 28 HCP between the hands, it is hard to see how slam is plausible. Also the 3NT bid seems to deny any slam inters.