I don't know what the local fauna looks like, but I'm curious if it'd be possible to start training trees or vines across the bridges as a way to gradually replace the ropes with something more durable - I'm thinking something like the Root Bridges in India[1] that last for centuries.

I worry with projects like this that the first version's easy enough to build and show off, but if you don't keep up with the ongoing maintenance you're right back where you started within a decade, and "monkey bridge maintenance" is an easy budgetary line item for the "fiscal conservatives" to go after.

[1] https://www.atlasobscura.com/articles/living-root-bridges-in...