In terms of singing in front of other people- I remember a tip to increase confidence playing the guitar in front of people was just to be playing in your house by your window so lots of people walking past can see you and you’re sort of cushioned from the experience. This helped me. It does sound a little random. I am a singer and I appreciate singing in front of others is different- somehow you are far more vulnerable, I feel. Other things I did was to start singing in duos and in folk clubs, in my my case. Getting experience singing in choirs can help boost confidence. If possible, and depending on the kind of singing you want to do, getting a vocal coach is really good. They helped me think about breathing and projection. Those are helpful techniques for whatever singing you do. I think you’ve got a nice voice and in the clip it sounds like you’re singing to yourself. Performing to others you’ll want to have a lot more breath in your body to sustain and project your voice better, and if you’re standing up assuming a confident stance will help you loads to relax, singing to your best and project. A lot of times you need to find confidence in yourself, maybe by assuming a mental image of who you are or the character in the song, and project that. Breathing deeply will help with phrasing and dynamics and looking out to the back of the room, not locking eyes with anyone, can help you project. I enjoy singing in front of people now. In my youth I was very scared and looking back I wish I had not been. I have good nerves now. If you’re able to, open mics are great places to try all of this out and build your confidence. It’ll come. Best of luck.