The charger getting pretty hot is normal on these as they draw up to about 180W of power, just make sure the charger is not surrounded by any objects which may block cooling during charging...
Yes when you transport the bike on/in a car it uses almost the same amount of battery as if you were riding the bike, so keep that in mind.
Hosing directly in any electrical componet on the bike is long term a bad idea, a damp cloth in that area is much better option ...
I use it for more than a year, I absolutely love it, shifts perfectly, it's very robust and reliable system. I already lost the battery cover once, but then I have found it weeks later. So yes, there is possibility you will lose one, but it doesn't protect that much after all, in fact many axs...
Yes, 2020 Expert is also in black color, I think new 2021 models were released somewhere August/September 2020 so yeah, yours is about a year old model at the time of purchase ...
Here are specs of 2020 Expert Carbon: Turbo Levo Expert Carbon | Specialized.com
For the wheels you only need to know following:
both wheels are 29" and most likely 30mm width
front hub is 15x110mm BOOST and rear hub is 12x148mm BOOST
you need XD driver on rear hub so you current cassette will fit
I recommend ratchet type of driver as it is more durable as pawls
2019...
If it's a last update then there is only update for the battery firmware, I wouldn't bother much, just wait for the next oprotunity to go to LBS (for some other issue/service) and do it then...