Here are good tips and best practices to follow when cleaning your e-bike. While the bikes are made to handle getting wet, they still have sensitive electrical areas that need extra care to avoid damage.
How to wash your e-bike.
Always turn off the bike and leave all the connectors plugged in as if you were riding (they're more sealed up that way). This doesn't apply to SL bikes that have no motor/battery plugs visible.
Gently wash the bike with low-pressure. Your garden hose with the sprayer on Shower mode is fine. Don't use Full, Jet or Laser Beam modes.
Avoid spraying more sensitive areas like the motor/battery plug, handlebar remote and display.
After washing, wipe dry the motor/battery plug (non-SL models) before reconnecting. You could also wipe them dry and leave unplugged to air dry. Wipe clean the speed sensor magnet on the rear disc rotor (be careful not to touch the rotor surface with contaminated rags). The magnet can collect brake dust from the metallic brake pads over time.
Wipe dry the bike and clean and re-lube the drivetrain. Avoid aerosol lubes as overspray can easily contaminate rotors. User a bicycle-specific chain lube.