Your Oukai is a Hisun board https://epoch-power.net/ that was sold under the “Waviator” brand in Germany since 2018 (efoil prehistory). Using a Maytech 3 button remote in 2021-2022, in 2023, they are using a Flipsky VX3 one
Their current Alibaba page with prices where you could ask for spare parts…
'https://cnhaishang.en.alibaba.com/productgrouplist-806327747/EFoil_Surfboard.html
including their 2023 model in EPP (Waydoo look alike) for 3100usd
The forum search function: 32 hits
'Search results for 'hisun' - FOIL.zone
A couple of threads could be helpful:
Aug 2022: @EdwinOlding tried to fit a Maytech V2 remote:
'Hisun Alibaba E Foil Repair- Maytech V2 Upgrade
Feb 2020: @pacificmeister et al tried to tweak the remote receiver :
'Hisun efoil remote mods anyone?
Dec 2020: @mattgalic tried to equip a bare board with a Gong foil:
'Matt's 1st build, France - #16 by mattgalic
Today, if you use your battery (needs to be tested) + Gong foil the best option to equip this board is probably a Hobiba all-in-one kit with a 65161 motor and with their new remote when we know the price :
'All in One efoil kit from Hobiba