There is a way to get rid of Steam, but you won't like it. Did that trick for my wife a while ago, back when Steam issues prevnted her from logging in way too often...

Basically, you need to log into your account (not the game, the account page on the website !) using your Steam credentials. Once logged in, once you're sure the account knows it's you, it knows you own the game and whatnot, once you're absolutely sure it'st he proper account... You need to buy the base game again.

Yep, you read that right. The only known way to get rid of Steam is to buy the game again. Maybe wait for a sale or something, and make sure you buy the BASE game, not an extension, chapter, DLC, whatever.

You should now own the game twice, once through Steam, once "normally", which turns your account into a frankenaccount and allows you to launch the game from the launcher and not through Steam. You will have to re-download the whole game from your account, though, can't convert the Steam version to standalone version as far as I know of.

You will, of course, keep all characters, progress, every crown, every upgrade, chapter, DLC you own. And you can purchase your next upgrade, crown batch, whatever, from the website instead of Steam. No promise it will work forever, but it's been well over a year for my wife, and it's still working to this day.