For those who wants to customize the paint, I think one has to find out the OEM other than contacting VOOK.
AFAIK a lot of Chinese brands are just sticking a sticker, and if they really care, do some UCI certification using the branded frame name. AKA, pretty much the same as western brands, but less attention to some details/designs.
(I hate Aethos frames that are priced 5500 AUD here, but really love the clean and clever DI2 wire exit hidden behind the FD hanger, and no Chinese Aethos clone is really copying that.)
Thus those brands will not provide any paint customization.
Some branded frames have some known OEMs that you can contact directly.
Onirii One frame with external or internal cable routing -> 朝昇碳纤维, CRF51 (owned and loved, OEM allows extra frame modification with extra fee)
Bigrock non-team version (owned) -> Failed to locate the exact OEM, but microck is selling the same frame with lower price
Avenger -> Hongfu (Not sure if Hongfu still accepts direct orders, but Avenger pricing is reaching western brands)
Permeants ST-09 -> LTK266-D-SL (owned)
Although no OEM can be found for VOOK, considering the price, I'd say it may be very close to OEM price (all above mentioned OEM prices are already over 3000RMB).
I'd be completely fine with their branding on the frame, as long as the frame is mostly black. (But again, I can never tolerate any frames without dedicated FD Di2 wiring exit, maybe until Shimano goes full wireless next gen)