Recently i read a paper about the OOTA/RFUB problem for memory_order_relaxed atomic variables. Nothing related directly to your question, but a clear warning about how concurrency can be a nightmare if you don’t stick to good practices and if you go in the UB world.
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1217r0
YouTube / < A Relaxed Guide to memory_order_relaxed - Paul E. McKenney & Hans Boehm - CppCon 2020 - YouTube >
< CppCon 2016: Hans Boehm “Using weakly ordered C++ atomics correctly" - YouTube >