I am sorry you are struggling but honestly your only options are either quit or snap out of it. I don’t know if it’s necessarily inhumane. Calling it that sounds extreme. I mean it’s annoying but I am not sure if it’s cruel. Not like they made you clean toilets all of a sudden even though you weren’t hired to do that.

It’s been only 3 weeks. You getting paid more than many people will ever dream of (despite working very hard demanding jobs) and if it means looking up blog articles for few weeks then maybe just do it for awhile. Did you ask them to give you more tasks? But then again you just said no to something that could be more exciting than articles. They might be collecting evidence that you don’t want or can’t do other tasks.

Plus maybe you can bring them a new letter that you can resume normal activities. You did give them a letter that stated you can’t do hard tasks. They might be scared to push it

Don’t do anything drastic. Talk to your boss re adding different tasks. Take a weekend off and then resume your job in a new spirit next week