Firstly, I wasn't looking at the bundle with the soundtrack, I was looking at the total of the game plus both DLCs, which before tax is about $40 CAD (which is about $30 US), but the bundle with the soundtrack DOES equal approximately $25 USD, so that's alright then.
Secondly, I know Steam is going to hit me with 15% tax as I'm in Canada, and I was hoping that Itch wouldn't, but I suspect that after conversion and tax it'll be about the same as it is through Steam anyways, only with more hassle. So I'm just going to go ahead and do it on Steam right now! Thank you for the answer! :)