You can pay for dreamhost, namecheap or any other shared hosting plan that provides WebDAV. Some provide unlimited storage. I am not sure how realy unlimited it is.

Buy domain and host empty website. Turn on ssl using hosting tools. Dreamhost provides you with free certificate for that. Namecheap charges after 1st year.

Create directory on the website using hosting tools and turn on webdav on that directory. It can be password protected. Turn on password protection and disable public access using hosting tools.

That will give you a disk that can be mounted on Windows, Linux or mac. From home or coffee shop. It will act as your remote storage and you can access it using Explorer or Finder. Most tools will read content of remote disk without any restrictions.

Create another directory and leave public access to have public sharing directory only you can change (keep passwords).

Create another directory or use one of your private subdirectory with application Joplin and you get free and open source notes and todo system. That system can encrypt all your notes with master password. I recommend it: joplinapp.org

The might be other apps…