Is it possible to make a simple OS alone using c++ knowledge from sololearn's c++ course?

Answer 1

No not at all; and no C++ course alone can give you knowledge for building even simple OS. There is multiple layer of abstraction involved between
hardware -> firmware -> driver -> OS -> App

Answer 2

Knowledge from sololearn xDDDDDD

"Is It possible to get job using knowledge from sololearn"
Sure !
2 cheese burgers and one cola please :P

ahh my epic english <3
The meow ! :D

Books or Videos on YT !
Sololearn is useless xD

But best way to learn is by trying to enter any code and broke sm1 else code !