Hey there @ms2000bk , welcome to our forums! Thanks for reaching out. I understand you are trying to launch Anno 1800, but you've found it to redirect you to Steam. That's really unusual!
Just to make sure, are you certain you purchased Anno 1800 via the Ubisoft Store, and not Steam? From what you've described, it sounds like you'd purchased Anno 1800 on Steam initially, and now when you are trying to launch it via Ubisoft Connect, it is trying to launch Steam. Most likely from there, you've got Steam automatically logging into a different account than the one you'd purchased Anno 1800 on.
The best thing to do would be to get in touch with our support team directly, as they'll be able to have a look at your account to see what is happening, and help you track down the missing copy. For data security reasons, we can't do that here publicly on the forum - it needs to be a private chat. Please get in touch at the links below. Feel free to send a link to this forum thread in your message to us, so that the support specialist who responds will be able to see what has already been discussed. It'd also be helpful to include a screenshot of your order confirmation for your initial purchase.
Open a support ticket with Ubisoft Help
Send a Twitter DM to Ubisoft Support
Send a Facebook PM to Ubisoft Support
Let me know if I can clarify this further