A good chunk of engineering is putting together reliable systems from unreliable parts.
You build in safeguards, redundancy, defense in depth, recovery systems. You build models of the system and prove characteristics about it.
Software is fundamentally automation. LLMs enable automating the construction of software itself. They're much faster and cheaper than people, and they're more unreliable. (People are unreliable too!)
The immediate challenge of these times is figuring out how to reliably construct reliable software in the large, over the longer term, reliably. This is an engineering challenge, and the only way we'll get to the other side of it is by trying to do it. Things will be rough, there will be a Cambrian explosion of techniques, most approaches will fail, and many more won't survive as models improve on quality and capability. But we'll figure it out.
Making things by hand, as in the time before agentic coding, can be engineering too, but it is not the core challenge of these times, and it will soon be a hobby, or possibly a kind of luxury good. You will no more want hand-written software than you'll want a hand-made car. It will not have the precision, performance or reliability of machine-made software.