I didn’t realize I need the same thing until I read your post.
AgenDAV is in maintenance mode, but they also say:
New features may be added by PRs however. New features may be proposed in issues tickets, send as Pull Requests, and the maintainers will review and presumably merge them. PRs for bugfixes are welcome and will be reviewed & merged.
I’m going to check it out.
The fact you mention security features, without ever saying it’s ‘super secure’ tells me you know a lot about what you’re doing. I’m so sick of apps like this that start with “most secure app on the net” but you know they’re delusional. Thank you, going to check this out.