I also found it difficult to nurse without any support. I’ve been using a nursing pillow at home and whenever we go out, I do take it with me. I know some would find it ridiculous and unnecessary but it’s not bulky and looks neat so I don’t mind. Makes our life easier.
As someone who had a very large baby finding a chair with an arm and propping my arm on that or with my leg helped
I use a Boppy nursing pillow and recommend it