There's 2 ways to link accounts. Cross save & account linking, they're different things. You may have it linked & deactivated cross save, or unlinked but not deactivated cross save. Go to settings, accounts & linking, & see if anythings there under steam. Then go to cross save & it'll show what's active accounts wise. If it's active it will show a time when you can deactivate it or reactivate it. There is a 90 day cooldown to reactivate but it's to the minute so if it's exactly days it could drop off later today. Without seeing your settings it's hard to pinpoint but the steam account is still at the very least linked in some form, I can see your Xbox AND steam characters so it may be just be linked. Easily unlinked by how I said above, that should in turn free up adding another steam account for cross save.

Did you unlink or did you deactivate cross save? You still appear as having cross save active & it wouldn't if you'd removed it correctly.