I found it interesting wandering around the ancient sites in Egypt to see what survived 4000 years. Granite was the easy winner followed by heaped structures of softer rocks.
The problem with that for architecture is most structures are meant to be occupied, and being inside a heaped structure of softer rocks isn't very nice. I do wish that I got to see a structure meant to last millennia built in my lifetime. On that timescale, I _just_ missed Mount Rushmore.
If so, I think plenty of buildings will survive. If not, it’s a strangely specific definition to me, since still standing but un-maintained and unused isn’t a goal I would shoot for.
Considering how many structures from thousands of years ago are still around, I'd be shocked if there weren't any 21st-century buildings standing thousands of years from now.
Rebar makes buildings a lot stronger, but also has the unfortunate property of rusting. That makes it less strong and expands it, damaging other parts of the structure. It also is more or less everywhere.
Also, modern buildings often are designed for a given economical lifetime. If you order a structure that can be maintained for 50 years at $1M a year, that’s what you will get. You likely can keep it standing for centuries, but at ever-increasing maintenance costs.
On the other hand, we are building so much that, statistically, something will be standing thousands of years from now.
If your message is “there are forces at play which can erase your civilization entirely from the face of the earth” then no, it’s “just enough” engineering.
