In combination with the exercise it sounds like you're doing anyway, have you tried a bit of Yoga and a bit of listening to meditative sounds before/during bed/sleep/end of day? You may have tried similar things already, but if not, maybe worth a go? It's not going to pass/waste time as such, but might put you into a better position to stop your mind racing with negativity, especially in that crucial pre-sleep phase.

Particularly looking at "Yoga for Anxiety" or "Yoga for Mental Health" type things, moreso than general strength and fitness Yoga. You'll find a bunch online. You might find something like this Yoga Healthcare Alliance 10 Week Course works for you (it's promoted by the UK's NHS for some conditions). It's focusing on basic de-stressing, de-tensing muscles, breathing focus, and may help you feel calm and relaxed - which may give you a good nights sleep - which could potentially do wonders for beginning to recover.

I'd also suggest combining it with some "sleep headphones" - a fabric headband with some really flat headphone speakers inside it - then listen to a combination of "meditation for anxiety" or "8 hours deep sleep ambient soundscape" type things whilst you lie there.

Ideally you'd do the Yoga sat on your bed, then drop straight into something like "a nice man tells you you're great and everything will be fine" followed by some sort of "inner peace meditation that lasts 8 hours or longer". Obviously, you'll find your own preferred voices/sounds. I've also used white noise style "starship engine sound" or "on a night train" audio.

If you watch them on your phone with "Newpipe", you can save them as videos or just as audio files - which you can then set up as playlists in VLC. No point in downloading the same thing every night.

This whole set of things might not work for you at all, but if you're up for hours anyway, what do you have to lose?

Personally, I found this process helped me massively on my way out of a similar patch (combined with exercising more, quitting caffeine for a while, CBT therapy - it was a multiple angle approach).

Regardless, I wish you luck and pass you my best wishes in your recovery.