I agree.
I believe it is ok to tell her you love and are there for her if she needs you, BUT her behaviour is NOT acceptable.
IF she CHOOSES to behave in such a way, she will have to ACCEPT the CONSEQUENCES.
These consequences can be a variety of things.
No lifts.
No money.
Buy her zero treats.
Stop do her lunch.
Stop doing her laundry or anything that benefits her.
A home is more than one person and there is absolutely no way that I would allow one person drag the whole atmosphere down.
If she has issues or worries, absolutely encourage her to tell you and let her know that you will help and listen in any way.
HOWEVER, you will no longer accept her rudeness and disrespect and that you will no longer facilitate her within the house if she doesn't cop herself on.
I have 4 children teens-20's and have had to have a variation of the conversation above when necessary.
None of them have been as extreme as you describe, but that is because I will nip it in the bud quickly.
I have found a very fast reversal of rudeness when "operation zero tolerance" is instigated.
The not buying treats illicits a quick response as does "get the bus" etc.
Making their lives less comfortable is most effective.
You do her no favour accepting this.
In my experience from friends, it only gets worse, so being kind, but VERY firm is the best policy with children.
Teens are largely inherently self absorbed and will only change their behaviour through self interest.
Making their lives less pampered hits the spot IMO.
So in response to any further rudeness just disengaged and refuse her requests for anything.
She thinks she can behave poorly and you will suck it up.
This is a very bad message to give her.
You have feelings and are allowed to be hurt by her behaviour.
As she grows up, her friends won't be long walking away if she takes that attitude with them.
I never show anger, I just start saying No to everything and take a break for myself😁.
Will you drop me somewhere? Nope.
Where's MY lunch? No idea.
Is my laundry done? Nope
Are there any treats? Nope.
May I have money for X? Nope.
You get the idea.
Do NOT bring her to McD's and take that opportunity to tell her why and that you are finished tolerating her appalling behaviour.
Do it calmly and then let her see you mean business.
IMO children of all ages respond well to boundaries and knowing where they stand.
Good luck!