In bridge slang, a "Turkey" refers to a poor, possibly naive player. In this case, it is a U.S. National Champion, but since the event was the 2019 European Championships in Turkey, I couldn't resist the title. Furthermore, there were not one, not two, but three mistakes made by declarer, so maybe "turkey" is appropriate. Actually, three strikes in a row at bowling is also called a "turkey." Our (non)hero held:

 A3
 Q1097654
 --
 A932

Both sides vulnerable at IMPs, his partner dealt and passed. RHO opened 3 and he overcalled 3. LHO bid 3NT to play. Partner raised to 4 which came around to LHO who doubled. Against 4 doubled, the K was led:

1087652  J  Q7  KQ65

A3  Q1097654  --  A932

Not bad at all. Those 6 HCP in hearts and clubs are a pretty sight. Declarer trumped the diamond lead and played a heart. Dummy's jack won (East playing the 3). Now what? Declarer crossed to the A and played the Q. West won (East showing out) and played a second diamond. Declarer ruffed and played another high heart. How did he do? Not well. This was the Real Deal:

Vul:Both Dir: North	1087652  J  Q7  KQ65
QJ  AK82  K1052  J107		K94  3  AJ98643  84
	A3  Q1097654  --  A932

West won the second high heart and played his J. East astutely overtook and played a third spade. Declarer was doomed. West's 8 was promoted into the setting trick.

Where did declarer go wrong? Actually at three points! His goal should have been to avoid the trump promotion. Declarer should have made the contract. How? Let's count the 3 ways.

He could simply discard a spade on the opening lead of the K (loser on loser). This would mean East could never get on lead in spades. With that chance missed, when declarer's J won, he could have gotten out his scissors and played the Q, throwing a spade (letting East win). Again, that would prevent the trump promotion. And third, when West did win a high trump (and erred by continuing diamonds instead of playing a spade), declarer again could have discarded his spade loser on the diamond. Zero for three by declarer!

What about a spade opening lead? Declarer can simply duck and win the second round. The contract is always makeable.

Notice that if West "sacrifices" in 5 it will make on a heart lead.