How frequent are the crashes? Are there any error messages or popups? I would be a little shocked if it was steam that was causing the problem, but you can download the demo here on itch, and if that works and the steam version doesn't, I can help you get the full version in direct messages.
I'm guessing this is your steam profile? https://steamcommunity.com/profiles/76561198849074049 (I noticed you posted on steam too). Make your games public so I can confirm you own Aground on Steam (edit profile, my privacy settings, and set my profile and game details to public), and I'll give you an itch.io copy of the full version. Once I confirm you own the game, you can change your privacy settings back if you'd like.