I have put harnesses on pups and a leash and tied them to me.
I also have put a carrier up on the top between the pillows, but that requires keeping them in it.
If you message YT member bonbon and ask her about bed rails, I am sure she has lots of information. She sadly has lost Alex, her sweet baby that she had the same issue with...I know that she had looked into bedrails for him.
For years I slept on a mattress on the floor after my Maxwell had the disc surgery. I slept on the floor many times with sick pups...I SO get it. haha
I am SO happy to hear that Cobi is doing so well!
