Board Game Arena

I completed a turn playing the last card in my deck, which gave me the 5th signet. My opponent's card effect did nothing to alter the situation, so I was left with 5 signets at end of turn. However, I lost the round. Is this the correct ruling? It seems like the 5 signets should be counted before my lack of cards triggers. Maybe I'm just wrong and that's okay! Thanks for any help!

The game ends after the application of the effects of the losing card...which was the last card of you opponent? If it was a card that forced you drop cards you loose

The user manual states the following:
"The first player to obtain 5 Seals on their cards wins the game."
Then, in the "End of Round" section, it says the following:
"At the end of the round, draw 1 card from your deck"... [...] ... "If you cannot draw a card, you do not lose the game."
The game is determined by: 1. The opponent cannot play a card, you win. 2. A skill indicating "You won the game" is used. 3. You have 5 or more Seals on your cards at the end of the round.

I believe the former explanation was wrong. I don't believe having to discard cards that you don't have looses the game. You can discard 0 cards. However your opponents last card was most certainly "Puppeteer". In that instance you must have a card to be able to play in place of your discarded card or it counts as you not being able to play, which loses the round. This literally happened to me in a 4 to 0 signet round
The reason it's confusing is the game gives you the signet first before taking it away because of the Puppeteer.