OK so I currently have a 9 year old VI kid so I'll give you some recent experiences

Don't do silver metal, wood, cement and sand playground
https://www.google.com/search?q=malahide+castle+playground&client=ms-android-vf-ie-revc&source=android-browser&prmd=imsxvn&sxsrf=AOaemvK9Vps0Y5uPtm8WL4EULlItxv3B5w:1631564433255&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjcjuOT4_zyAhUpQEEAHTPLALwQ_AUoAXoECAIQAQ&biw=412&bih=732#imgrc=qN05_QuL2R5CtM

The grey and beige colours blend, each step would need to marked on the edge.

Shiny metal can have alot of glare also which can affect a VI person

Swings for me were always something that made me flinch as the VI child can't see the swing coming back, maybe if the swings were fenced off

Bright primary colours are good

And don't ask my why they exist but for any child it's lethal, on raised wooden bridges/walkways there are often horizontal beams right at a child's eye level, usually the same colour as every other part of the bridge (I presume for structural integrity)
Anything a kid can whack their face off should be covered in a foam IMO (beams, top entrance to a tunnel), however at exit points (tops of slides, fireman pole platform, narrowings/barriers are very helpful

Trip hazards, try to have the ground level, & as few bolt's sticking out of the ground as possible https://www.google.com/search?q=bolts+sticking+out+of+ground&tbm=isch&ved=2ahUKEwiO6cr75vzyAhVCXcAKHah3BDkQ2-cCegQIABAB&oq=bolts+sticking+out+of+ground&gs_lcp=ChJtb2JpbGUtZ3dzLXdpei1pbWcQAzIECB4QCjoHCCMQ7wMQJzoFCAAQgAQ6BggAEAUQHjoGCAAQCBAeOgQIIRAKUJITWJ1FYN1GaABwAHgDgAGGBogBxjySAQ4wLjExLjcuMy4yLjMuMZgBAKABAcABAQ&sclient=mobile-gws-wiz-img&ei=kLY_YY7hD8K6gQao75HIAw&bih=732&biw=412&client=ms-android-vf-ie-revc&prmd=ivsxn#imgrc=5VEeGEmk8f1CEM

I was a kid who was too embarrassed to use my cane, and one time I sprinted face first into the play structure and broke the shit out of my nose. I would have wanted a safe way to run without worrying about tripping or hitting things. Also, since blind people are missing so much sensory input, sometimes they seek stimulation from movement. For some people this manifests as rocking back and forth. As a kid, I had a trampoline and swing set where I’d spend hours. I think safe and exhilarating ways to move would be great. I’d also experimenting with ways to keep kids oriented. Maybe with different materials under foot so they can find what they’re looking for. Would love to hear the ideas you’ve come up with so far

Mainly it's just everything a normal playground would have. I would suggest bright, well contrasting colours, and textual things that a child can feel around them (fabrics on walls and stuff).