Best ground surface for a DIY climbing frame area?

[Teamustbefromateapot]

Looking for help / recs for a surface to put under climbing frame. We are surprising my children with a climbing frame for Christmas and can't decide what to do for the ground surface!
The area is to the side of our house and the grass is terrible quality. There are some paving stones we need to lift too, so we thought about boxing the area in with some kind of play bark / wood chip, but just can't decide what to choose as we will be DIY-ing too.
Options:
-Rubber Bark
-Wood Chip bark / mulch
-Fake grass
-Rubber mats

Please help, there seems to be an overwhelming amount of both pros and cons online and we just don't know what to do! We've been told any bark will need to be fitted after the frame, unsure if this is the case for other surfaces.

Thank you!

Grass/mud. Bark will be a cat toilet. Fake grass can burn feet if its in direct sun and i think is laid on compacted gravel base so could be hard to fall onto. Not sure about the rubber options but i think they could be expensive and will be as safe as falling on mud i would think?

I think shredded bark. It will cause fewest injuries. It will eventually rot down, so by the time the children have grown out of the climbing frame, you can dig it in or add it to your compost or mulch.

Cats are territorial, so get your own houseproud and aggressive feline. He will keep his own grounds clean, if trained to avoid the bark, and other cats will not trespass.

Sadly no cat and I don't think I could convince hubby! That's my only concern re the bark

Def don't want them on mud, maybe we just need to returf 🤔

Try the real bark and if there is a cat problem then move to fake.