This is an interesting perspective but I think both are necessary. At different times in my life (perhaps correlated to the "brain eras," though I'm still a bit skeptical of the details here) I've needed others for development and contentment, and at other times, I've needed to focus on self-love and solo happiness as you describe.

Whatever your "meaning of life" may be, it's not the estimation of you that other people have that is important, but we are incredibly social creatures. Life is really not possible for individuals of our species without some level of society and community. Even Christopher Knight - the North Pond Hermit in Main who lived alone without human contact for 27 years - survived by burglarizing cabins and camps and was eventually reintegrated into society.

I guess my point is this is a dialectic. Both can be true, and both are true. The "trust almost 100% with all of myself" might be debatable, but "I could not do it with at least one other person" seems kind of obvious, as does "Learning to be happy alone is vital to becoming an adult."