I played for a bit, I think I have a grasp of your general direction with your game.
The visuals are really great, it's a pleasure for the eyes and even though there no combat and no challenge to the player's expansion yet, it's really fun to try and optimize your placements between your buildings and the hexes like the wheat fields.
The cards were a bit hard to read for me, I found the text a little too small, and the numbers of the IU (meat, gold, etc) were not aligned to their respective label, but that's easily corrected.
It's not directly related to your game, but on your game page on itch, I think you forgot to check the option that allows the player to make it fullscreen. Because of that, it was bit harder to play and see the cards. If you haven't already, you should edit your game page and check that option, it will make things easier and it doesn't count as modifying your game in regard to the jam rules.
There's something I'm not sure I understood : on one hand you have an "end turn" button, but on the other it seems like after you've played your cards, you can wait indefinitely and reap some bonuses every X seconds. Is the end turn button used only to draw more cards? If so, those cards could be drawn automatically once you've played your current hand.
All in all, even if it's unfinished, I think it's very solid and interesting as a concept, I would very much love to see how far you will take it should you decide to continue working on it. As a fellow gdevelop user I can tell there's some impressive programming under the hood, you can definitely make this shine. Thanks for sharing your game!