Haryyanga→Brihatkarma→Brihaddarbha→
Brihatmanaa→Jayadratha→Dridharatha→ Vishvajit
(Stayakarma)→Adhiratha→KARNA→Vikarna.

Adhiratha was born of Brahmin mother and a Kshatriya father according to Harivansham.

And KARNA was adopted by him.

THIS is KARNA's family's lineage which also had ancestors like King Anga and Romapada.

He was not brought up in poverty and he WASN'T a Nobody.

He was the rightful heir of Anga.
Duryodhana just fastened his coronation.

His family was a Kshatriya (though his father was a Suta).

THIS is how royal Karna's family actually was.

Thanks brother @arnab_epic for providing me with the references.