You don't need sotware engineering to build successful software, until you do.
In my experience you don't need to know a whole lot about LLM's to work them. You need to know that everything they spit out is potential garbage, and if you can't tell the good from the garbage then whatever you're using them for is going to be terrible. In terms of software terrible is fine for quite a lot of systems. One of the first things I build out of university in the previous millennium is still in production today and it's horrible. It's inefficient, horribly outdated since it hasn't been updated ever. It runs 10 times a day and at least 1 of them will need to automatically restart itself because it failed. It's done it's job without the need for human intervention for the past many decades though. I know because one of my old colleagues still works there. It could've been improved, but the inefficiency cost over all those years is probably worth about two human hours, and it would likely take quite a while to change it. A lot of software is like that, though a lot of it doesn't live for so long. LLM's can absolutely blast that sort of thing. It's when the inefficiency cost isn't less than a few human hours that LLM's become a liability if you don't know how to do the engineering.
I use LLM's to write a lot of the infrastructure as code we use today. I can do that because I know exactly how that should be engineered. What the LLM can do that I can't, is that it can spit out the k8s yaml for an ingress point with 200 lines of port settings in a couple of seconds. I've yet to have it fail, probably because those configurations are basically all the same depending on the service. What a LLM can't do, however, is write the entire yaml config.
Similarily it can build you a virtual network with subnets in bicep based on a couple of lines of text with address prefixes. At the sametime it couldn't build you a reasonable vnet with subnets if you asked it to do it from scractch. That doesn't mean it can't build you one that works though, it's just that you're likely going to claim 65534 ip addresses for a service which uses three.