Sooo I got to AR 30 and what the hell am I supposed to be doing now? I'm suddenly underleveled/underpowered for everything. Can't farm Storm Terror, too hard. Can't do the last quest I tried (The Chi of Guyun), too hard. What the hell is up with the balancing in this game? It's pretty easy until hitting that mark and now I can't solo the meteorite event things (lowest levels went from 25, now to 35 minimum) to get more fading stars might...So again...what the hell am I supposed to be doing now? Where did I fuck up?
I'm running DIluc + Barbara + Chongyun + I can use either Razor, Xinglang, or Fischl. Diluc, Razor, and Chongyun are level 40. On Diluc I have the Aminus Prototype at level 20, and my artifacts are set up well enough...
I would switch up your team comp for now to Diluc, Xianglang, Fischl, and Barbara. Fishl is a SS+ tier support (Oz) Not sure which bows you have but use something for now with high attack. if you find overloaded is annoying try, chongyun + diluc for melt. Xianglang is there just for the 25% increased attack. Barbara for heals.
The biggest mistake I see players make is spending a ton of resources into support characters. For example. I'm AR47, main DPS is Keqing at lvl 80. my supports are sitting at 60still (just for the final talent).
You should only focus on mainly 2 dps MAX. In your current situation i'd say only focus on 1 if you can't clear the current content.
My recommendation to you: Diluc is arguably the best character in the game. Poor all of your resources into him. Make sure Diluc has his weapon to the current max (60), his level (60), and his talents (level 4?) Farm your crystal ore (every 2-3days) if you need more crystals for weapon exp.
Don't forget Co-op exists within this game if you're having issues doing the fishcl crystal event. No shame in getting help until you get stronger. Once diluc's level increases with his weapon you should notice the game will be easier given how it calculates damage. I had trouble initially with storm terror however I would worry more about gearing your carry for now.
Edit for Artifacts: Please do not farm artifact domains until AR 45 (if you plan on playing longterm / semi hardcore). Use a mix of what you have currently and prioritize the feather (attack) and hourglass (attack) until you decide to go optimizing (pyro cup etc.). Don't worry about crit/critdmg until past this point. The true endgame of Genshin is min/maxing your artifact sets for the best ratio of 1:2 crit chance/crit damage. You can also do a daily artifact route (youtuber: taka gg) if you have most of the map explored for artifact fodder.
You should always prioritize ascension materials, talents, experience, money(if needed) so you have everything prepped for the next AR level. The good news is, at AR35 you need to do the ascension quest to ascend the world level. So you can sit on level 3 if needed. I don't recommend delaying the world level rank up but if you need to you can until you have everything sorted out