What would be the approximate cost for a partial renovation?

A gas pipeline is being laid on the street this year. The house is also already registered for a gas connection. We would also choose a gas heating system.

I would cancel that very quickly. Even if you get a gas supply contract, no one knows whether gas can actually be delivered. Read up on the topic, prepare everything with the still running oil system for conversion to a heat pump, and then switch. Getting gas now would simply be throwing money away.

I have electricity more around 20 in mind, the rest can be roughly about right. I would think twice about doing new gas if you have to get to radiators etc anyway.

I wouldn't use gas anymore now. We built in 2006. Back then, people still built with gas and condensing technology. I am currently racking my brains about how to convert. Completely rebuilding in the existing building is absolutely not feasible price-wise.