Hi @filipe23353816
I will really question the need to long emails from a business perspective, not denying the issue though, what you might have to do is a treat your outlook profiles differently from your other target profiles: outlook you would put the pixel at the bottom, other you would put the pixel at the top.
Otherwise, I think this will have to go through Adobe Engineering to correct.
You could try to not use the pre-header field in the Email Editor and try to make it via a HTML block at the top of the email but not sure this will do the trick from a pre-header point of view.
Sadly, you don't have much alternative that I can think of.
Hope this helps,
Thanks
Denis