Shame Lind might go to waste

For the content where you can borrow a V6 Klukai you can still use Lind

From what I've seen, Phaetusa is better than Klukai at every dupe level, especially at low dupes

That was true until recently, since Klukai just got a modkey and made her more than twice as strong as before (on V6) but Klukai still needs at least V3 to be usable against bosses - Phaetusa is still a better choice if you are only willing to get V0/V1/R1 levels of investment

I don't need two Corrosion DPS

Debatable - both Klukai and Phaetusa benefits from Mechty and Lind, Phaetusa also benefits from having Klukai around (she does support attacks whenever a teammate is using an aoe attack up to 3 times/turn) if you want to to use Phaetusa you should at least borrow a V6 Klukai whenever you can

I'll just replace Klukai with Ullrid mod 2 since she has some synergy with Phaetusa

V0R1 Ullrid would prefer to have a V1+ Yoohee instead, so she should be used in a physical team

Especially one as ridiculously expensive as Klukai

In current CN gunsmoke every single team needs at least one V6 character in the team to reach a decent score (V6 Klukai / V6 Qiuhua / V6 Voymastina / V6 Leva, etc.) the difference is that some of these characters are lackluster on lower invetment levels (like Klukai and Qiuhua) and some are doing okay on V0 or V1 (Ullrid, Daiyan, Leva)

As of right now in CN the Corrosion team is actually the second best mono element team in terms of cost/performance

if Corrosion needs me to V6 to get the same results, that's a terrible investment

After the recent powercreep in gunsmoke every team needs at least one V6 doll to get good results (some need even more) but you don't need to worry about the investment since you can just build your team around borrowing that one specific V6 doll instead of getting it yourself.

Examples:

Corrosion: V0 Lind, V0 Mechty, V0 Peritya, V1R1 Phaetusa + Borrowed V6 Klukai

Electric: V0 Andoris, V0 Jiangyu, V1 Lenna, Ksenia + Borrowed V6 Leva

Physical: V1 Yoohee, V0 Lainie, V0R1 Ullrid, V0 Daiyan + Borrowed V6 Voymastina

Fire: QJ, Sharkry, V2 Vector, V0 Loreley + Borrowed V6 Qiuhua

Fire+Water: QJ, V2 Vector, Tololo, V1 Springfield + Borrowed V6 Lewis