I use Anki mainly for learning vocabulary, so there is no confidential information to the extent of credit card numbers or classified nuclear weapons details. But the data nevertheless reveals some information with regard to my reading habits (e.g. there are some bibliographical citations).
I know such use cases should not warrant much consideration relative to other more important issues affecting people on a large scale. But I still wonder whether it should be considered feasible to initiate a crowd-funded (e.g. gofundme) effort towards implementing end-to-end-encrypted sync. If people turn out to be willing to contribute financially towards this feature to yield a sufficient bounty, then it can be implemented. It is a significant feature and so I don’t think crowd-funding would be overkill.
I cannot self-host the current non-E2EE sync server as I do not have a permanent residence with a suitable internet connection.