I agree though that the title is too much and less funny in retrospect, I wish I chose a more tame one. Humorous annoyance on personal blog posts translates badly to submissions here.
The UK left the EU a while ago. UK citizens traveling to the EU will require an ETIAS authorization which also comes with an app at the end of the year, but that's not live yet. The website that's been prepared so far does mention the ability to file online, though.
I am not a native speaker, so my interpretation might be wrong, but I tried to evoke the semi-serious but good-natured "You went to the bakery? You better brought me a snack as well!" meaning with "better have", not the "must have" meaning.