And C tends to reinvent object oriented programming with each library so you might as well use language defined classes.
So I don't really see the point.
You don't need to use stuff like concepts, or "showing off how smart I can be with template libraries" (looking at boost), but C++ has a lot of features that make it much more productive than C.
Sticking to plain C has the advantage of probably being the subset of C++ (I know, it’s not technically a subset) that’s in widest use.
Is it not? I thought C++ was explicitly a strict superset of C?
More importantly, though - the syntax is not what matters. The languages are very very different in idiomatic use. You just don't write programs the same way with C and with C++. And the gulf between the two only expands with time. A decent C program is almost certainly a poor C++ program, in terms of idioms, utilization of library facilities, and sometimes even in terms of performance (!).
Look at for ex. what const means in each, or auto. Or variable length arrays (feature that doesn't exit in C++). Or designated initializers that C++ didn't have for a long time.
Here is a good list of differences: https://mcla.ug/blog/cpp-is-not-a-superset-of-c.html
There are plenty of legal C programs that aren't legal C++ - if for nothing else, then because C++ has more reserved keywords which are perfectly legal identifier names in C.
E.g. this is legal C but not legal C++:
int template = 10;
I prefer using C++ like "C but with cin and cout" and I informally call it C+ :)
Garbage collection, big runtime, and non-zero-cost FFI are acceptable trade-offs in many areas of programming, but they are deal-breakers for domains where C (or Rust) is necessary.
Rust is somewhat similar to C++ in the feature set, but not in complexity. Rust's features are more orthogonal, without duplication and backwards-compat warts, and you get hand-holding by the compiler.
Technically you could be right about complexity vs. feature set, but from the POV of someone that's using a simple language, the two don't look that different. One does help you avoid certain errors, although whether that counts as hand holding or hand slapping is in the eye of the beholder.
* creating more work for yourself, and
* introducing bugs in your code.
Don't do that. Use C++ as C++.