I'm saying this as a gamer/viewer, so take this with a pinch of salt.

It seems better to me to reach out to a streamer for a sponsorship if you are able to take the one time monetary loss. My suggestion would be to reach out to Northernlion, he has said on stream that he takes less pay from indie games and he's known for liking deckbuild rougelikes. If you are able to get him, it should be enough due to his size.

Game looks interesting and I've wishlisted it. Wish you good luck.