This. Its like trying to keep three distinct languages (C, old C++, new C++) in one's head at the same time. It is much better use of one's mental energy to spend that effort on three actually distinct languages that are, e.g., tuned to different domains and use cases.
Imho the C++ community needs to address this or eventually become irrelevant as people gravitate to more sane and user-friendly ecosystems. Not sure how that can be done without breaking some eggs. My preference would be for a simplified and streamlined C+++ that tackles this complexity head on.