I dunno, it's already pretty good at writing code and only going to get better. I agree with your conclusion though, mainly because as a software engineer writing code is actually not even the most complicated part of the job. If an AI could write perfect code every time it'd make my job a lot easier but I'd still have to do a significant amount of work such as:

Figuring out which code to write in the first place! Work discovery if I'm senior enough or clarifying requirements.
Co-ordination with other teams. Depending on the exact work this becomes more or less important
Managing the lifecycle of a change including testing, deployment, monitoring and triaging issues.
Ongoing maintenance. Staying on top of upcoming changes in adjacent or foundational teams, making sure our stuff will keep in working.
Architecture design. You mentioned this in your post, understanding interactions with adjacent systems and how to organise our own systems to meet current and (reasonable) future requirements.
Conducting non project work such as interviews, involvement in working groups to help decide overall technical direction of my group, upskilling myself and those around me.

That's just off the top of my head, I'm sure I've missed some things. As much as I love writing code I honestly feel like if an AI could do that part it'd just take stress out of my day and give me more time to focus on those other parts of the job. Of course in reality more work would probably just be piled on but that's just life I guess.