Depending on your definition of “using”, you may not actually be able to, at least for now. If CPPReference's table[1] to be believed, there are still important features that are either missing from GCC and Clang or implemented “partially”, which may mean different things for different features and compilers.

In my personal opinion, unless you're doing the project just for fun, it seems better to stick to C11/C17, at least for the next few years.

[1]: https://en.cppreference.com/w/c/23#C23_core_language_feature...

In the embedded world it’s still a struggle to get people to use C99, maybe in 20 years for us.

Yes. The idea behind most of the stuff seen in C23 is to rid itself of UB that ultimately lead to easier to maintain better compilers and libraries.

While in practice it may take long for some things to follow the standard, it is certainly a step in the right direction.

This is my humble opinion.