feeling hopeless about lack of confidence

I feel like I'm pushing back against lifelong lack of confidence and never winning. My parents always tried to push us down in confidence, they were always angry at anyone who stood out and acted loud, confident or funny, and they believed people should be quiet and humble,and they pushed our sense of humor down and any attempt to stand out, they were obsessed with being "talked back to" and were angry all the time that kids should be seen and not heard, etc.

I've been doing self help courses, self hypnosis/NLP, meditation, etc for over 10 years now, and I feel like every gain I make is temporary and some situation comes along to push my confidence down again. At work I see how funny and relaxed other people are and I feel so different and unable to be like that, and I see how far from that I am.

Every job i have I shrink from responsibility and pass every difficult decision to someone else, I have problems with any confrontation/difficult conversation, fear of trying new things, every job I have, I see people who joined 6 months after than me, taking on more responsibilities, making friends and being relaxed being close with the other colleagues, while I'm still hiding in corners, avoiding difficult tasks and friendship.

I had a bit of a breakthrough last year where I felt that I'd come into my identity, I was going to a fantasy fan meetup and movie fan meetups, being with friends, talking more loudly and confidently, feeling like myself. I was going to this fantasy author meetup and I felt like my new self-image as an (amateur) author gave me lots of strength and I "knew who I was". But then I'm at work and everyone is loud and making friendships with each other when there's people I'm still too scared to ask the name of.

I read a lot of self help books and I do try to see friends a lot, and I very luckily do have good friends, but depression and social phobia overcomes me sometimes. I just worry sometimes all these new breakthroughs I get from self help courses and new interests, fantasy author, martial artist, spiritual person, they're always temporary,they give me a boost for a while, then they fade away like a disguise I can't wear anymore. oh man I'm emo now.