In my opinion, C++ syntax is pretty readable. Of course there are codebases that are difficult to read (heavily abstracted, templated codebases especially), but it's not really that different compared to most other languages. But this exists in most languages, even C can be as bad with use of macros.

By far the worst in this aspect has been Scala, where every codebase seems to use a completely different dialect of the language, completely different constructs etc. There seems to have very little agreement on how the language should be used. Much, much less than C++.