how would magnus do against Beth Harmon?

How would Magnus do against a fictional character?

He would win on time. Fictional characters can't press the clock.

In the Queen's Gambit universe, Beth Harmon has plot immunity, so she would not lose to Magnus.

In our universe, it seems like it's Magnus Carlsen who has plot immunity.

I suppose in the Queen's Gambit universe, it's Magnus Carlsen who is the fictional character...

Beth would beat him and then invite Magnus back to her hotel room for drinks and analysis after which the next morning she would find that he had left without making breakfast and later Magnus would reveal that he stole her notes and then defeat her in the rematch.

     Carlsen would win easily. Anya Taylor-Joy (the actress played Beth Harmon in the film) certainly wouldn't be able to beat him unless he was willing to make whatever moves the scriptwriters told him to.

+1

As talented as fictional Beth Harmon was ... she'd lose due to her outdated theory.

Magnus has been honing his openings, these days, with neural-network engines ... meanwhile Beth was still playing lines straight from her dusty copy of Modern Chess Openings (9th Edition, circa 1957).

I can see Beth Harmon Magnus in some lines.

I agree with you all; magnus would easily cream beth in an all out battle!

Magnus would lose. He wasn't even born at the time whenTQG takes place.

Carlsen will win, how can Beth Harmon defeat the world chess champion? 

I believe that Magnus Carlsen would beat Beth Harmon in chess and then make love to her. The following scene could happen.

"Your chess is insane." Beth said, as she slipped her feminine hand into Magnus's pants and smirked. "Are you trying to mate me?" protests the World Champion Magnus, as Beth Harmon blushes, the girlish figure undressed before Magnus. "Weak tempo play, Beth." The two kissed, deeply and passionately, and afterwards Magnus places his Rook into her open line.

I would watch that. Then probably shoot myself.

You have provided one answer to a more intriguing question:  

How would Magnus do Beth Harmon ?

Neither weak nor slow, lol!

Many chess enthusiasts do say that Magnus is well-versed in all types of positions.  Apart from that, game 6 of the WCC shows that he can keep going for more than 7 hours.  Lol.

Why would you shoot yourself ?

It depends on whether or not Beth Harmon is sober or not. If she's clean and sober, she wins. If not, Magnus takes her out.