It sounds like it wasn’t fermented long enough. That’s what puts the sauer in the kraut, otherwise it’s just salted cabbage. How about using it in a modified cottage pie? Sautee whatever veggies strikes your fancy — chopped celery, spring onion, fennel, a nice sharp green like mustard or radish or the rapini I continue to be obsessed with. Since you don’t eat meat, you could use Quorn crumbles or TVP for a protein element. Add it to the veg and brown with a splash of Worcestershire or soy sauce.
Enhance the sauerkraut by mixing it with horseradish and any spices (carraway is classic) or fresh herbs (parsley, oregano, thyme, even mint would be great as long as you had a light hand with it) you like. Put the sautee mixture in a casserole dish and add a layer of the improved sauerkraut, a layer of cheese (I’d go with a strong Swiss like an aged Ementhaler) and top with a cauliflower mash. Bake in the oven until the cheese is fully melted and the pie is bubbling along the edges.