Don't understand your comment, for sure, since the change to passport eligibility rules is only and entirely due to Brexit…

“Tough European rules on passport validity for “third countries" now apply. Unhelpfully, there are several different interpretations of the rules.
The basic requirement from the European perspective is simple: “You will need a passport valid for at least three months after the date you intend to leave the EU country you are visiting, which was issued within the previous 10 years.”