"admittedly wrong" is correct and commonly used in written English.
It is typically used to acknowledge or concede that something is incorrect or mistaken. You can use it in a variety of contexts, such as when discussing a mistake or error, acknowledging a differing viewpoint, or admitting fault. Example: "I have to admit, my calculations were admittedly wrong and I apologize for any inconvenience it caused."
As Balfour admitted in a secret memorandum in August, 1919, "So far as Palestine is concerned, the powers have made no statement of fact that is not admittedly wrong, and no declaration of policy which, at least in the letter, they have not always intended to violate".
I also voiced an admittedly wrong assumption within the article itself that it wouldn't attract many eyeballs, and yet it became one of my most viewed pieces this year.
I have, admittedly, been wrong about the USC team already once this season.
In what, admittedly, has not been a classic period for new music from the continent, she has succeeded as a stylish performer who hasn't put a foot wrong.
Will the IRS somehow punish the preparer who steps up and admittedly gave the wrong advice..
For the next few days I would wake (admittedly, at totally the wrong time for my UK-based body clock) with a profound sense of loss, which took a few seconds to pin-point to the outcome of the vote.
Admittedly, if used for the wrong causes or taken the wrong way, it can be disastrous.
Admittedly, not everything has gone wrong in Russia.
Admittedly, there was not much wrong with the old control system, but it still seems lazy not to even try to innovate.
"I know of her story … we all have stories," Williams said, getting the tone wretchedly wrong in an admittedly stressful moment.
Admittedly, something had gone quite wrong with their site: a page asking me to "restore my balance" urged me to click "continue" and then "click the red 'restore my balance'" link which … led me back to the original page with that instruction.
