For the most part, becoming a sorcerer is impossible. You either already are one, generally by birth, or you never get to be.
Meaning it should not be possible to multiclass into sorcerer.
im going to quote the players handbook on this, and tell you exactly what page, that shows how you are just flagrantly wrong.
And being wrong is not a democracy, or a thing you can have an opinion on... you just have incorrect information. Its like saying "all bards must be horny"
PHB, page 99
"MOST <not all> of the time, the talents of sorcery appear as apparent flukes. SOME <not all> sorcerers cant name the origin of their powers, while others trace it to strange events IN THEIR OWN LIVES <not their parents>. The touch of a demon, the blessing of a dryad at a baby's birth or a taste of the water from a mysterious spring might sparkthe gift of sorcery <literally none of these are hereditary>. So too might the gift of a deity of magic, exposure to the elemental forces of the inner planes or the maddening chaos of limbo, or a glimpse into the inner workings of reality <again, none of these are hereditary>."
Reading comprehension helps, I can think of a dozen events in game that could justify every sorcerous origin.
Nowfor page 100
"Is it a family curse, passed down from your distant ancestors? or did some extroardinary event leave you blessed with inherent magic but perhaps scarred as well"
