[Streamline] is nice utility, bringing Vex Armor cost below 100 Energy, the amount restored in a single pulse of a Large Squad Energy Restore.

Toxin Energy is recommended for reload and holster speed. Heat for +HP is good too if that's in demand. [Chroma] is used for boosting Credit gain, Saryn is the meta for speedrunning PT, so [Chroma]'s build is mainly about convenience for farming.

If you're using [Chroma] as a credit buffer for a squad with [Saryn] you can skip Blind Rage and add Stretch instead, for better squad buffing range (swap slot with Adaptation to line up polarities). Streamline->Augur Reach is also a good swap for that use-case.

Build can ofc be optimized more by adding polarities, allowing higher rank Adaptation, but Adaptation Rank doesn't matter much, it stacks up to 90% resist at all ranks, only the % per hit (5-10%) and duration (10-20s) scale with rank. And changing polarities will cause compatibility issues with other important builds.

PT builds:
Saryn/Chroma/Wisp
Zenith
Kuva Nukor
Contagion Zaw
Mausolon
Smeeta(for credits)/Adarza(for speedruns)