Thanks for writing this up. I believe that intention also matters. Although there’s no difference in terms of the contribution towards suffering, I would treat myself and others differently between accidentally eating non-vegan food vs willingly eating the same food.
I also think it’s important to consider the use of animal products in society. In your wool example, do you believe you have a responsibility to instead donate the wool to avoid others from purchasing wool that does lead to harm? As long as non-vegan societies exist, is it possible for the use of any animal product to be ethical?
Practically, in the real world, I find it easier to draw the line at avoiding the use of all animal products. Even if there may exist animal products that are ethical to use, I find it easier to adhere to the simpler principal of total avoidance. I also think total avoidance helps contribute towards activism. Being seen using animal products, however they were obtained, may enables other to legitimize their own use of animal products.
Even though you don’t know what code is running on their server, the bitwarden client used to communicate with their server is open source & auditable. End-to-end encryption only requires that the client code is trustworthy.