Edit: Goodnotes and Notability also have this annoyance.
If you need WebDAV I think Documents by Readdle will do it, and maybe even makes the share available to other apps though its File Provider. But I'm not sure what parts of Documents are subscription based now since I have a paid copy from before it went subscription.
It even has the option to keep a local copy of folders from network shares so you can use them offline, which is a pretty handy feature if you're working with large files or don't have a cellular iPad.
Not a problem on a real operating system, everything just works. No need to pray the developer followed this years best practices instead of 3 years ago best practices just to use files in a sane manner. No need to beg a developer to fix it either, because the system was designed in a non-broken way to begin with.
Because let me tell you, it ain’t this one. Windows & Linux routinely run into this & per your rant… shouldn’t.
Yet they do.
Give PDF Viewer a look if you want better file handling: https://apps.apple.com/us/app/pdf-viewer-annotation-expert/i...