Really glad you're taking leave. I've been so so bored with this time so this question is def very helpful.

It's been difficult for me to learn a new hobby because anxiety builds up with each mini failure. That might just be me though. I would suggest taking long long walks if you can. Rewatching a tv show (critically acclaimed dramas have been my thing) might not be too stimulating.

People watching has been interesting too, and often leads to revelations about my own mannerisms and actions. You can do that by chilling at a coffee shop or similar.

Best best of luck! keep us posted on what you find is helpful.