LSEG (London Stock Exchange Group) Entry Level Software Engineer interview questions

I searched on LinkedIn for internship/entry level C/C++ positions and applied for multiple companies from which LSEG. I got a phone call to program an interview "to get to know eachother", which was a lie, it was actually a technical interview of almost 2 hours, consisting of incredibly technical and complex questions ranging from computer science idioms to particularities of implementations of std containers. There were 2 interviewers, from which a main one and a supporting one. The problem with the interview resides in the attitude of the main interviewer. He had only extreme reactions to my answers, either excitment or complete dissapointment and frustration, more often the latter. I would answer a question to the best of my abilities and fully disclosing if I didn't know the subject of the question existed. His reaction would either be to further complicate the subject and expect an exact answer (anything paraphrased or explained wouldn't suffice and would be declared wrong). On multiple occasions I would give a correct answer, but would not be explicit enough for their company technology standards. After all of this I get told at the end that the entry level position that was advertised was actually senior level. It wasn't an internship either, it was full time. Some examples of red flags in his attitude: Ignoring my CV and skipping the HR interview. Rolling his eyes, pushing around his chair and raising his hands when I gave unsatisfactory answers. Very vocally asking his partner "Is this even worth continuing?" after telling him I didn't know how to write a singleton class in C++ and 2 more times after for other answers. Ignoring my requests for further explanations or context to his questions and repeating the original question. There were 24 questions, but selected only the most important ones.