Hmm try to start small like play a game, interact with people there and be friends with random players. Immerse yourself in some comment sections, like debate and argue with people.Like those overtime can build up your confidence, in social interaction at least. I doubt you're boring if you're in a manga site so you probably like anime and stuff, which is something most people would relate to.
Try talking about your fav series, current issues and your political opinions with other people to make friends, gossip a little and I know those sound hard than said but yes, you have to change but take it at your own place. Take a deep breath everytime. I don't know about your insecurities in details , but I want you to know that you're gonna be okay. If people judge you and shit for those, they're assholes. Don't take whatever is said to heart.
I just wrote some long ass advice and accidentally deleted it all I’m so pissed rn but here’s me trying to put it back together ╥﹏╥
Look when you have insecurities it is best to talk to someone about it wether is a family member, a therapist or even me if you feel like talking or venting just email me in case you don’t have anyone else. Now moving on the the job matter company’s are not looking for someone social(depending on the job) their looking for someone with experience in almost every job application or interview they will ask you if you have any experience so if you are a college graduate or are currently in college I advise you to get ass much experience as you can. They will not only look at experience but also ambition/skill if you have been apart of any clubs or interred anywhere it is best to but that on your resume or mention it in the interview because everything counts and since the job market is pretty tight depending on where you live send your resume to at least 50-100 different companies(I know I’ve been saying companies this entire time but I just mean whatever your signing up for)and I’m not even exaggerating because most of them will decline(from my experience at least ╥﹏╥)and from the handful that do agree pick the ones that suits you most and if all of them decline then just try again. I know you have a lot of insecurities but when you get interviewed try to sound or present yourself as confidently as possible and I know you not that well spoken but you can search up questions the interviewer might ask and prepare you answers before hand.
I hope this helps (づ ̄ ³ ̄)づ
And if you ever need some one to talk or vent to just mail me (=・ω・=)

my insecurities and lack of friends have made me a lonely guy who cannot form words with boring ass personality. Do i need to change it , how can i ?? im scared i wont be able to get any jobs bcz of this