Are you near a university with a good School of Maths, OP? One that requires grade A at FM for admission?
If so there may well be some undergraduates who would make excellent tutors. You want someone who can put themselves in DC’s shoes, imagining what it is like to be struggling with this or that, rather than showing off their own knowledge. I don’t think you want anyone struggling - such a student’s time is better spent on their own work, anyway - but they need not be on a First. Someone nice.
It’s all about the rapport, which DC may find much easier to establish with someone close to their own age. In a tutoring situation, it is crucial that the tutee be open about their strengths and weaknesses, and receptive to tactful but honest feedback. Rapport is key.
What a UG lacks in pedagogical technique they may more than make up for by being able to relate well, remember their own experience of FM, and with enthusiasm.
Of course a UG should be well compensated for the niche skill of tutoring FM effectively, including both travel time and travel expenses (if they come to you). But the cost is still likely to compare well to a professional tutor.
I am biased, because I am a STEM academic and I made good money as a UG by tutoring. I enjoyed it, and all my clients came through recommendations so I think it was mutual.
In theory a PG, who may be doing supervisions, could be a great tutor also. However I was far too busy then and I think this is broadly true. I am sure some professional tutors are excellent.