Loving Vampire Crawlers! I've been addicted to it for the past week.
However, while playing the game on Series X, I've encountered a bug twice already that completely locked me out of the game, forcing me to restart. Posting this here in case somebody else is looking for this bug and cannot find any info online (I couldn't at least).
If you're in Capella Ultima, and make it to the final boss, The Ender, there's one card that can trigger a complete freeze state in the game. If you use the Clock Lancet to freeze Ender (eg. to prevent him from attacking during his turn), close to the point where he goes from his first phase to the second one, the Ender will fully disappear and leave the game in a stuck state. You can still shift through your cards, but you cannot choose any action, or press B to skip turn. You're just stuck there forever. Trying to press the Start menu to choose "Return to village" doesn't do anything. Pressing "Return to menu" will take you to a loading screen... and then the game will crash out into the Xbox Dashboard.
Luckily the game auto-saves right before this boss fight, and this is how I managed to easily reproduce the issue. Once I did yet another attempt, without using the Clock Lancet at all, I was able to proceed to the second phase and beat the game.
Hopefully this will serve for those stumbling upon the same problem!