Thank you very much!
Do you mean Riot Vanguard? If so, I just used to play League of Legends from time to time, but that has been a few years ago. Loved playing ADC but that game is really toxic when it comes to chat. Never tried Valorant as I´m not the guy for competitive shooters.
So Vanguard was never a thing, but yes I would not play a game if it needs kernel level permissions for anti-cheating. My years as an IT-Sec student have told me a lot of things about exploitation and I even wrote an elaboration on the technical process of malware and if software with such high permissions has just one security flaw, it can really open the gates for everything.

I answered, and I am not sure if you want some feedback, but i will give it anyway.

The question 'Please select which of the following digital game distribution platforms you use the most' is flawed, as it only allows you to select one platform. I use several equally, depending on the game I want to play, it’s not about platform preference. The wording also implies multiple choice due to the wording. I ticked one on random

The same issue applies to the question 'Please select which of the following game modification distribution platforms you use the most'. Again, it depends entirely on the game and where the mods are hosted. I use CurseForge, Nexus, ModDB, etc. but I have no real idea which one I “use the most,” so I ended up ticking one at random.

Also, since you're specifically asking about games, I would avoid using the word 'modification'. No one in the gaming communities typically refers to “mods” as “modifications.” Even 'third-party' feels a bit overly formal. When targeting a specific audience with a questionnaire, you should use the language that community actually uses to reduce ambiguity and increase response accuracy. Langauge like this is what you will typically use in your thesis.

As for the question: 'Please describe as detailed as possible how you were informed, e.g., about which incident, by whom, via which medium, the content of the notification, etc.' This is not well-suited for a questionnaire. It reads more like an interview prompt. The purpose of a questionnaire is to be quick to answer and easy to analyze, open-ended responses in large volumes (50+ participants) become difficult to code and interpret reliably, so not sure how you will analyse it. I skipped this question entirely, and I suspect I won’t be the only one, so I hope this is not central to your thesis.