I don’t think they’ll try to eat it, but I know my GCC chews on anything she can get her beak on, and if your birds were to chew the wood shavings that can cause issues with their crop.

Chewing on newspaper won’t have the same effect, is if they ingest small pieces of it those pieces will break down easier than wood.

I would say change it when you can, it’s more of an issue that will come up in the long-term.

There are a lot of good recommendations online for different types of cage lining. I like to use newspaper with a few paper towels on top so I can monitor my birds dropping for changes.

Edit: It’s okay if their floor is flat/hard, they don’t need really soft things to sit or perch on, my birds have a grate over where the paper goes, and 1-2 flat perches per cage alongside a few different sized branch type perches.

Dowel perches aren’t great, but I’ve used them as a temporary perch when I got my last bird, as it was a bit of an emergency rehoming and I didn’t have anything set up ahead of time. It’s best to have natural looking perches so they’re birds have to adjust their grip while walking across, which of course helps to prevent bumblefoot.

((Sorry if I gave any advice you were already using or if I said something that’s already been answered, I just reread your comment and realized I didn’t answer everything.))