Can multiple electrical issues be related?

2014 Kia Forte has had odd issues since purchased used in 2018. Can these
things all be caused by something like a single bad wire or contact
somewhere?

Horn from wheel worked, got quieter and quieter until doesn't work at all.
However, when using the key fob lock and panic buttons the horn is loud and
clear.

Front marker lights sometimes come on by wheel knob and sometimes not,
and take turns as to which is not working. However turn signals and flashers
from key fob work fine.

Passenger rear window mostly does not work but sometimes does.

Strangest of all the car sometimes will not start. This was totally intermittent
until today and i spent all day investigating and can not get a start. When key
is turned a faint click from the fuse box area of engine compartment is heard
but nothing else. Turning the key multiple (1 to 20) times would usually start
the car.