How did I get lucky?

The only option is to give away the copy. Everything else should be out of the question.

Activate the won key and do whatever you want with the key you bought. Gift it, trade it, refund it. Whatever.
Or reroll.

Both options are perfectly fine. You only can't gift the key you won.

In your hypothetical scenario I think the best thing would be to refuse the key and let the giver reroll. Since you've already activated your won key, though, you can do whatever you want with your extra copy from humble. Creating a giveaway is obviously the nice thing to do but you're free to refund and save some cash for the next game that catches your eye.

You can always allow a new winner to be chosen for a giveaway you win here. If you enter something by mistake or change your mind about a game and forget to remove entries for giveaways, you can simply leave a comment asking the GA creator to request a new winner and allow the key to go to someone else who will want it. In this case, you can let someone else win the key by asking for a reroll and activate your own key, or you can activate the key you won and create a giveaway yourself with your key you purchased or do whatever else you want with the key you purchased. It pretty much just comes down to whether you would prefer to have a win for this game on your SG account or activate the copy you purchased. Creating a giveaway with the key you purchased will make your contributor value here go up, but activating the win will also make your won CV go up an equal amount.

I pray for the mods here.

Ask for refund and add me to wl for advice ;)

I would make another giveaway with the key you still have.

While you could argue, that asking for re-rolling leads to the same result, there can be differences. First off, as giveaway creator I would be nervous if I already had sent the key. Because I am not sure if you have seen and used it. Second, the giveaway creator may also have leveled up and rerolling would decrease his level temporarily. On your side, you can consider doing the giveaway in the same form (public) or making it more narrow (forum giveaway in any shape or form for example).

Refunding the Choice, you could do as well. Not my cup of tea. Not sure if I have ever refunded something. But I am normally very cautious with any purchase and try to be sure that what I get is suitable (in taste and quality).

So yea, giving away the spare copy would be my personal way to go.

Thats a tough one and i think everyone would deal with it in a different way.
Personally i would do it like this:

I would refuse a reroll, ask for another copy and give away the refund!

And seriously, i dont like unnecessary rerolls etc and prefer to avoid more work for the mods.
Also i never refund anything. So from your 3 options i would just give it away and case closed.

View attached image.

If you've already activated the key, you're simply down to whether to refund the choice or not. If not, you can possibly do a GA for the same.
In the end it's upto you, but as we're on a GA site I feel like the last is always the best option. :)

I think its fine to just accept the win and you can just giveaway your own key from Choice (up to you though of course if you want to and are able to refund). It's probably simpler for both mods and the winner that way, and if you do a GA, that's just another chance for everyone again. You didn't break any rules and won fair and square.

Damn, you're so lucky, I've really enjoyed the first game (A Plague Tale: Innocence) and want to play this one too, but no money for Humble Choice 😂

check your friend list and see if anyone has it wishlisted, or if anyone played the first game and liked it, gift them the second.

You won the game so you have to activate it. As to what you do with the copy you bought, that's up to you.

All the gifts from SG should be redeemed to the Steam library (when region restrictions allow). But since they're gifts, they come with no strings attached. You don't even have to play the game you won.

You do what you want with your own copy of the game: refund it, trade it, sell it, let it sit, etc.

Give away your key from Choice. It's the least headache for you and the SG mods.

To win something out of 7149 entries is... wow!
It seems that when you do something good for others, life rewards you with badges or something else. :)

It seems that most of you (72%) think that I should give away my spare copy. And I agree with you, so I did, even before I created this post or seen the results of the poll. Since the beginning, there was and still is hidden GA for the A Plague Tale: Requiem. It ends in 4 hours, so there is still a bit of time to find it!

Congrats!
And thanks :D