Okay, well I’ll try to answer your questions as directly as possible.
Attending seminars to learn about current interests is a very clinical approach, that won’t ever really capture what those trends are and you will appear to be even more of an outsider imitating the ‘insiders’. I personally wouldn’t recommend it, maybe try looking to find a group hobby that you can do with other people (DnD, walking, photography, book club, sports, etc).
Are friends necessary, or not really?
Necessary is subjective. But at least for me I find having some social connections I can talk with helps, and is overall a net positive on my quality of life. Also good friends can end up being with you for life, certainly a good investment.
Also should I stop being in this environment and get a job instead?
That depends, why are you in University? If it’s purely for academic learning, just focus on your studies. If it’s to gain life experiences as well, go out and seek people. If it’s neither, and you can’t think of any other reason to be in such an environment than maybe a job would be a good change.