You can get one of these:
Here are 2 differant types of cover you can buy ,don't know how waterproof they are though
Sometimes i just pop a bag for life over the seat and battery, hook handle over a pedal, short bungee other side. Got a cheap cover too, but very fiddly & can blow off if not well bungee'd down.
And...Removing battery, especially on Bosch bikes means bike is almost worthless if stolen. At £700 for replacement no thief is going buy one to sell bike.
In case FS eMTB bike could be stripped for components and sold separately eg shocks, brake, derailluer.
If bike is stolen then you will have spare for you new replacement ebike, assuming insurance company doesn't won't battery.
I do think ebike manufacturers could do a better job of making bikes more secure. Smartmotion Pacer has security code to activate it, if bike is stolen theif will need to take bike to dealer to get new code.
All the factory middrives could do something similar with bike manufacturer coming up with their own interface eg pin or bluetooth app remote activation.