How much to spend on old house with lots of deferred maintenance?

Help! I'm paralysed with indecision, can't see the wood for the trees. So I'm looking for advice on next steps or who I could talk to.

My house is the worst in the street/area in a seaside suburb in Wellington, with alot of deferred expensive maintenance.

How much of my savings/kiwisaver do I sink into this place? Or just decorate not renovate? Or sell as is? Or create and rent out a 1 bedroom self contained space?

I'm 65yo, still working (government willing). But high rates and insurance and still some mortgage means I'd need to be working/have income to stay here.

I'd appreciate advice on how to navigate this, or whether there's a role like a property accountant or a really smart person to provide advice. Or other ideas.

Thanks!