Container Thread Safety

I'm aware of Container Thread Safety topic listed there: https://en.cppreference.com/w/cpp/container

But I want to know: can I use non-const member functions and const member functions concurrently without blocking (a mutex)? More specific:

1. Can I use std::vector::push_back and std::vector::size concurrently?
2. Can I use std::set::insert and std::set::size concurrently?

This doesn't make a practical sense commonly, but I don't need an exact result of size which I'll use, I just need a valid result at the time when I call it.

P.S. My doubts are come from there: https://www.cplusplus.com/reference/set/set/insert/ where they say for std::set::insert that

Concurrently accessing existing elements is safe

So maybe getting the size of containter is also safe.