Inscryption is not close to StS in gameplay style. It's more narrative and the card gaming strategy takes a back seat, it's also very breakable with certain strategies. Not to say it is a bad game, just it doesn't sound like it's what you're looking for.
Monster Train is a solid game, you'll get more replayability if you get the DLC later since it impacts core gameplay.
I would actually recommend you check out Griftlands, it feels closer to StS playstyle to me than Monster Train. In Monster Train it's a lot about supporting the units with your deck, whereas StS and Griftlands are more about using your deck for the combat.
That's kind of the sad truth of it though, once it is a useful and safe enough thing, you either pay for it or get left behind, it's dystopian as fuck, but it will significantly increase the utility of those who can get it.