Nextcloud doesn't verify your email and has tons of other nice features as well. ProtonDrive (/ProtonMail as another user suggested) probably doesn't or you could use your Proton address for that.
You mention allowing weak passwords are a plus. Please use a weak password, especially without email as 2nd factor.
Have you considered using mnemonics for your passphrase?
Generate a number (i would use around 5) of random words (EFF has a wordlist, humans are really bad at randomness) and link them together using silly images. For example:
- sparrow
- window
- automobile
First, you link sparrow to window: imagine a sparrow trying to break through a window, not just flying into it by accident, no, this sparrow is mad and is set to destroy it.
Second, you link window to automobile: imagine an automobile with huge windows. The car is completely normal sized except every window is at least 3 meters tall. It looks absolutely ridiculous and you feel embrassed that youvhave to drive it everywhere.
Repeat this proces for the rest of the words. It helps remembering them if the image makes you feel something, like making you chuckle or feel angry that you have to deal with this stupid contraption (only in your mind, hopefully)
Also, make sure each "link" is distinct. Eg. Don't make the second link an automobile driving into a window when the sparrow does the same. It will mess up the order and make you jump around between similar mental images.