Hi no-moving-lines, and welcome!
Of course nobody would want you to "run your health into the ground", that would be terrible! Hopefully you can find a dietician who knows enough about plant-based sources of nutrition that they'll be able to work with you to come up with a really healthy plan, rather than dismissing your wish to be vegan. Maybe you could ask them what their stance is on veganism is before you arrange a meeting, to avoid wasting everyone's time, then you can hold out for someone who can do their best to help you
I've never had to live on a diet which cut out nuts, soya and wheat all in one go, and I imagine it will take some work and good planning to make sure it covers everything, but there's nothing in any of those things that can't be found in other plant-based food sources.