She has a lovely voice. Based on the example you provided, I’d suggest something that’s extended at the top end but without a real presence peak. (I think most presence peaks will land right in the middle of a portion of her voice that might prove problematic.) A healthy proximity effect might prove useful to add body when she needs it.
A non-standard but very usable choice might be a ribbon with extended highs. An AEA R84 comes to mind. Because the HF response gets out to 16K or so but rolls off as typical for a ribbon, the trick is to boost with a shelving EQ at about 11-12K (experiment to find the point that works for her). And, since the R84 has no peak in the HF, you can boost A LOT without unpleasant side resonances popping up. Use a quiet pre to minimize noise. And the proximity of the ribbon will add “oomph” if she needs it simply by leaning in a little closer. And it fits in the budget!
Certainly worth a try.
As always, YMMV.