I am trying to understand what you are saying Friedemann which is difficult since we think quite differently I tend to look mostly at what I can do in a language, not at what I cannot do. There are always gaps in our knowledge of a foreign language.
Since when is handwriting a requisite of a B2 level? I must admit that my Chinese handwriting skills have declined since I wrote the exam 43 years ago. I essentially never write. For that matter I rarely write in Japanese, yet in both languages I consider myself between B2 and C1, although better in Japanese than Chinese in many ways. I do not worry about what I cannot do, and focus on what I can do.
You dismiss "passing a test" but do you have any knowledge of the British Foreign Service Exam in Mandarin that I passed 43 years ago?
Yes Chinese is more difficult than Spanish. That does not mean that it is some unbearably difficult task.
Re CEF levels:
B Independent User
B1 Threshold or intermediate
B2 Vantage or upper intermediate
C Proficient User
C1 Effective Operational Proficiency or advanced
C2 Mastery or proficiency
B2
Can understand the main ideas of complex text on both concrete and abstract topics, including technical discussions in his/her field of specialisation.
Can interact with a degree of fluency and spontaneity that makes regular interaction with native speakers quite possible without strain for either party.
Can produce clear, detailed text on a wide range of subjects and explain a viewpoint on a topical issue giving the advantages and disadvantages of various options.
C1
Can understand a wide range of demanding, longer texts, and recognise implicit meaning.
Can express him/herself fluently and spontaneously without much obvious searching for expressions.
Can use language flexibly and effectively for social, academic and professional purposes.
Can produce clear, well-structured, detailed text on complex subjects, showing controlled use of organisational patterns, connectors and cohesive devices