I'm thinking I invested in the wrong teams... before I go any further, here's who I've been focusing on:
Venti (69)
Razor (70)
Xiangling (60)
Barbara (60)
MC (70)
Kaeya (50)
I've got also:
Albedo (50)
Mona (40)
Chongyun (20)
Diona (20)
Fischl (20)
Noelle (1)
Sucrose (1)
Xinqiu (1)
Lisa (1)
Amber (31)
Is there a better team than first 4? It's almost always Venti + Razor + Xiangling + Barbara (or MC or kaeyta if needed). I got Albedo up to 50 just to screw around with him... Mona was just a random pull and I haven't done much. I get gear will be more important later, but I just don't really need it. Everyone has 4* weapons (Rust on Venti) except Razor has Skyward Pride.
If you're talking about normal, every day farming, here's my take. Looking at your choices to invest though, I honestly think your team is fine.
1. Venti: GOLD. He's always part of your team IMO, or anything that has a lot of people. He's not amazing when it comes to bosses though. However, he's not great DPS outside of his Q, but in a pack of mobs, his Q is off the chain dope.
2. Razor: Also very good, though Fischl if you have her at C6 is better if you're using Razor for elec support. If you're using Razor for DPS, he should be pretty good.
3. Xiangling: Are you using a crimson pike for her? If not, craft that ASAP and she'll explode in DPS.
4. Barbara: I personally don't like her, but she looks to be your only healer really. I mean, you have Diona, I haven't used her so I can't comment.
The others you have:
1. Albedo: Seems good, but I've not used enough, but it doesnt hurt to have a solid geo character. I think he's going to get absolutely wrecked by Zhong-dong-li after the 1.3 buffs though.
2. Mona: She's one of the only characters I don't have so cannot comment. She's got a great ass though, so she's probably good to just walk around with at the minimum.
3. Chongyun: Marginal overall.
4. Diona: Heard great things about Diona, but not used her.
5. Fischl: Amazing @ C6. Oz stays out when you switch so you can generate constant reactions. It's basically having a 5th team member for a period of time.
6. Noelle: Some people swear by her healing but I dont see it. Pass.
7. Sucrose: She's very good, though you probably wont have as much use on her since you have a Venti.
8. Xiangqiu: No idea, I've not used.
9. Lisa: Her only redeeming quality is that she's a slut.
10. Amber: She's only worth to get the bunny banner from her friendship 10! Other than that, worthless.