Hi OP,
Hope sharing this helps. Have name changed as quite a lot of detail!
Been there though DS got further through the process.
He was very upset and we gave him time to process his disappointment. Had a bad couple of weeks until he suddenly snapped out of it with an attitude of "I'll bloody show them".
Interestingly his other options were nearly identical (but swap Warwick for Durham). He got offers from all of them.
In the end he chose Lancaster, ironically at the same time I was doing a post grad at York (our own War of the Roses!).
Of the two I think Lancaster was much better and very underrated as uni in general. York is the nicer city, but imho Lancaster knocks its socks off in respect of the Uni (though you need to consider subject - for DS Lancaster rated significantly more highly than York in top 6 UK). The campus is much better in terms of facilities (massive variety of shops, restaurants, hairdressers, you name it it's there and the library is fantastic).
The accommodation is a much higher standard (all en-suite) with it guaranteed on campus in your first year and some students stay all 3 years but many choose to live in the city after year one and there is lots of choice that is well maintained and won't break the bank run by Lancaster Student Housing (n stark contrast to York where accommodation costs are very expensive and on campus very dated in some cases).
Cost of living is cheaper and you are 30 mins away from the Coast, The Lakes and Manchester by (regular) public transport.
Upshot was he was VERY happy there and though we can't be certain without a "sliding doors" effect, I think even Cambridge would have found it hard to beat the positive experience he had there.
So where are we now....well he ended up with a First Class Degree and is now a post grad at.....yep Cambridge in the same college he applied to as an undergraduate 😀.
He has already got a prestigious job offer when he finishes having been accepted to intern over the summer (based on his Lancaster academic record not Cambridge - they agreed to defer the job offer for him to go after he was accepted - so no, top jobs are not always Oxbridge dependent!).
So a different path but he got there in the end! He's enjoying it and doing really well, but actually says he preferred the general vibe at Lancaster though he admits that whilst he coasted to his First there, he's actually having to put in "a bit" of effort at Cambridge 😂.
So give your DD some time, but also some hope. Like my DS she may end up taking a different path to end up at the "dream" destination and doing that might actually be a more positive and rewarding experience.
Best of luck!