been interested in electric bikes for years (not MTB). If you look at a frame, make sure you can source the matching motor and battery at a good price, because usually, you can't. Also, it's lithium, so import shenanigans are a completely different ball game. Whenever i looked at something, the MOQ was high, the seller was unwilling / unable to provide the hardware and so on.
Afaik, it hasn't become easier or cheaper.
Also, there are several instances where an OEM advertised a frame to then take it offline because a company bought exclusivity rights, so there's absolutely stuff behind an information / connections wall.