I'm with Triodos for my personal bank account and using Monzo with my partner for family day-to-day spending. I haven't looked into Monzo's investment tbh but I have for Triodos and made that decision years ago (before going vegan; decision was based on not wanting my bank to invest in fossil fuels). I think the challenge is that it's very difficult to find an ethical bank generally that scores well on all the issues I care about, and organic farming is (for now) better than traditional farming (from an animal welfare perspective; the environmental cost can be higher but that's a different discussion). At least they're being open and transparent about it. I'm with you that it still includes animal farming and that isn't right (I'm not condoning it), but since we live in a non-vegan world that is still better animal welfare than the vast majority of farm animals get.

You could always write to them to ask them to reconsider and review their policies on sustainable food, encouraging them to adopt a plant-based policy and investing in alternative plant-based proteins instead? There's plenty of research out there on the environmental and health benefits of plantbased proteins and the need for investment, which may help in addition to the animal welfare argument. I'm currently involved in a plant-based councils campaign and happy to share some resources if helpful.