I just got through a surgery and I’ll stay the next three days in bed, so I’m looking for a lighthearted drama to binge watch but my undecided self is finding really hard to pick one :)

If you could help me that would be awesome

https://mydramalist.com/dramalist/chucklotterstein/plan_to_watch

When The Weather is Fine and Prison Playbook, maybe. From the ones I've watched and which you have in your PTW list I would say those two are a good choice. Prison Playbook was a really fun watch for me, humor was on point even though it deals with some serious issues at times. 

I'd recommend the BLs Fukou-kun wa Kiss Suru Shikanai! (very lighthearted and fun) and Cherry Blossoms After Winter (heavier but still quite cozy). I wouldn't call Perfect Marriage Revenge lighthearted but it's very enjoyable and the end is satisfying so maybe that one. And Love in the Moonlight as well; it has some heavier moments but quite a bit of comedy and it's not too dark, imo.

Put Your Head On My Shoulder is my go-to choice if I'm feeling down. Heck, just the first episode has me smiling.

Terius Behind Me - a spy hiding from his own government develops an unexpected friendship with the young mother across the hall in an apartment complex. The National Intelligence service can't compete with the playground parents. Cutest six-year-old twins ever!

The Go Back Couple - a divorcing couple find themselves back in university directly before they met. Mentally they are still themselves 15 years later.

Even though SKY Castle is my favorite drama of all time and on your To-Watch list, my recommendation for a good light-hearted watch is going to be "She Was Pretty" -- Choi Siwon is side-splittingly funny in it, and just the overall vibe of the show (and the BGM for that matter) is so sweet and fun.