Hi Ann, the fully enclosed cover as on the black FS bike, are actually surprisingly good at keeping the mess out. If maintenance was neglected, you could gradually get a build of mud inside, but the electrics have never once had mud or water on them.
The motor on the white hardtail is far more exposed, but the electrics are still very protected.
An area that does get a build up of mud, is inside of the battery housing block. The connectors frequently get wet, but this has never presented any issue for me. The build up inside of the block is surprisingly fast.
If using an Intuvia display, the up/down remote switch can get mud behind the outer facia/bezel. You wouldn't be aware of this until it becomes tricky to switch between modes. No water gets into the electrics.
Water can get between the console and mount on the Intuvia display, but again it has never presented an issue or problem.
The down fall of the Bosch motor (or any ebike motor) when used in regular off road European conditions such as above, is the outer bearing on the chainset side. Just as with a normal/analogue mtb, this is a vulnerable area. Here in the UK, any mtb is going to require bottom bracket bearings at least once a year, and this seems to be something that many people forget, or don't understand. The Bosch outer bearing seal mod, is to my mind a bodge, it does help, but won't prevent bearing failure. The key to preserving the outer bearing is to never get any form of detergent or oil any where near it when cleaning or detailing the bike, and never ever use water to via hose or pressure washing to wash the motor down. The best way of cleaning is to unhook the chain from the front sprocket, and clean the area by hand with a cloth, and nothing more. I also remove the outer bearing seal at least once a month, remove the grease and any unwanted particles, regrease, and reinstall, applying a little extra grease over and above. It might sound like a pain, but in reality it takes very little time to complete, and is the best safe guard that yo can have.