I would have no concerns regarding the NiCd battery and spare parts are available. Upgrade to LiPo is a nice challenge technicalwhise, but it is too much effort for what benefit? My opinion.. The 230 has two packs in it, that means 4600 mAh, enough for a little more than 2 hours - even with the ESP on board.
If you have some additional forums regarding the motor control- let me know!
My next step is to build in the ESP32 with the cam (I know the ramdomnerd site and tested the software already), control the mower with it and stream the video. I plan to use the Tasmota for it.