> the single best improvements over the years have been atomics...

Of course, libatomic and friends have existed for a long time. Real question: Do you feel that the standardisation of atomics within the C++ base library is a material advantage over using libatomic? Also, maybe there are atomic APIs in the C++ base library that are better than libatomic. If so, please kindly share an example or two. I would like to learn more.

EDIT

I forgot to give a hat tip to your big upgrade from C++98 to C++23. In some projects, that can require an enormous amount of effort! Can you share a "stories from the trenches" that were difficult in that upgrade?