It’s sounds like your friend’s a bit jealous of you, which is actually rather toxic.

You’re not flirting or sleeping with your profs, so I assume you’re doing well because you’re studying hard andcompleting your work.

And someone who knows you as well as your best friend should, shouldn’t doubt those facts.

I’m curious; why would she be clocking things like your "held eye contact" in class, instead of concentrating on her own work ?

And what would she have to gain, personally ? Okay, on general principle she doesn’t like that maybe attractive people get extra perks and attention.

But her best friend is successful in school—why would she want to sabotage those results, as your friend ?

She's not exactly right, but that's not to say she's entirely wrong either.
There's been actual studies done that prove there is definitely an advantage to comeliness as an attribute.
It's akin to the whole White Priviledge thing.

Knowing that you have this advantage and allowing it's benefits to favor you is not inherently wrong. Just as it's not wrong for a white male to accept a job offer if he knows deep inside that another non-white candidate is more qualified for.

We all must play the hands we're dealt.

I don't think you've done anything wrong.
It's hard to tell if she's toxically jealous or if she's mentioning it all in a manner of intellectual debate.
That's for you to decide.

Best of luck.

Be well
Live happy
Keep trying,
Rob

Sounds like your friend envies you to a degree.

Sounds like your friend envies you to a degree.

‘Smoke em if you got em’..

Interesting question... Is there a difference between using your looks compared to using your brains to get through life?

Looks, brains, friends, or money, use whatever you've been given.

If you are able to leverage looks to achieve more favourable grades then it's your professors who are corrupt. If they are doing their jobs properly and with integrity then your looks would be of no value to your education.

I don’t understand why your friend thinks she’s the arbiter or right and wrong regarding personal beauty habits or person to person interactions. In the best case, the recipient of your good looks, eye contact, smiles or possible flirting would be the only person affected, and so the only person who could render a judgement, if any. In other words, if your professor or strangers don’t tell you to stop, or say you make them uncomfortable, it’s not really anyone else’s business. Is it?

If she knows you're not flirting as an advantage, then what else would it be other than jealousy? I think it's admirable to work for what you want and not use your looks to get it.

Your professors should be above this. Clearly they lack professionalism.

They are there to assist you in your education. Nothing more.