I'd support doing MFL with another subject. It just gives you more options long term (in my experience).
I wanted to do Economics and French, but I wanted them to be combined i.e. I could talk about economics in French rather than them both being taught as entirely separate subjects. So I declined Cambridge and LSE for this reason. Instead I did European Studies (Economics) which was joint honours in Economics and French (or whatever language you chose) with a smattering of law, politics, maths, history thrown in. This was at Kent which (at the time, no idea about now), was the leading uni for the course. Also helped by it being quicker to get to France from campus than get to London (pre-Brexit days sob!)
I was recruited as a grad by one of the Big Four, and after that moved into banking in the City. I've used my French a LOT at work but it's always been seen as a bonus rather than the basis for hiring. It got me transferred to the Paris office for a leading global consultancy. I now make 6 figures in the City and still use my French today (I work for a bulge bracket bank but several of my key stakeholders are French). But I'm invited to meetings because of my business skills rather than my language skills. To be honest, in Financial Services it's such a global melting pot that multi language speakers are ten a penny. So if FS is a direction of interest, you'll need a lot more than language fluency to stand out.
By contrast, my same age cousin did pure German at uni and became a translator. She still translates part time (rest of the time she does a sport) so it worked well for her as she wanted a different work-life balance to me.
One thing to also consider is where your DD's year abroad might be. I was sent (after having to pass multiple entry exams grrr) to Sciences-Po in Paris, one of the grandes-ecoles. I must admit it was brutal (exams every 2nd Sat afternoon, sob!) but has stood me in good stead ever since as it carries huge kudos in France and it's opened a few unexpected doors for me. Not the same for my fellow Kent students who went to Grenoble - but they are much better skiers than me
. I was very jealous of them at the time.
I have quite a few friends who did International Business with Languages at Heriot-Wat in Edinburgh. They've all done astonishingly well for themselves and it seemed to attract a very strong, smart intake of students (again, not sure if this is still the case).