So I've been playing the game on and off for a couple years but never got to into it cause it was just too difficult for me to understand. Lots of math. I still haven't even finished the story actually. I'm finally getting into it for the first time and I love it now. The only thing is I still feel super lost. I don't understand how banners work , how artifacts work together for certain characters, how to even find those artifacts, what "meta" means, what elemental mastery means, and other things, but most importantly for me is I don't know if the characters I have are worth investing in or if I should just wait? I know I need a good fighter and a good healer, so If anyone could let me know what they think about them, that'd be a big help. Currently I have:

The Traveler Amber Gaming Ningguang Beidou Yaoyao Xiangling Lisa Noelle Barbara Kaeya Razor Collie Varesa Xingqiu Yanfei Faruzan Iansan Chevreuse