I was pretty sure that there is something and a lot of searching finally led me to the "Unfair Commercial Practices Directive" from 2005. There also is a guidance to that directive from 2021 that is found here: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A52021XC1229(05)
Section 4.2.7 (dark patterns) is what is interesting for this topic. In the paragraph at the end of the section it includes the sentence:
unsubscribing from a service should be as easy as subscribing to the service
So it appears that the EU intended it that way but because it's only a directive, implementation differs by country. I also didn't see anything about being able to cancel in the same way you subscribed(e.g. that they can't force you to call or send a letter if you subscribed online), but afaik german law has a ruling like this.
Edit: I took so long to write this and find the links that I forgot the german law was the reason for the comment I answered...
Fast richtig. Karfreitag war nie ein allgemeiner Feiertag, nur für Angehörige bestimmter Religionen. Das wurde gestrichen(war auch ziemlich unfair), dafür kann jetzt jeder seinen "persönlichen Feiertag" bestimmen, den der Arbeitgeber nicht ablehnen darf. Man verbraucht dafür aber trotzdem einen Urlaubstag, der ist nicht extra dazu gekommen. Ich kenne aber persönlichen niemanden, der von dieser Regelung Gebrauch macht.