I do understand it, but you put yourself in a false dichotomy at the same time. You say you have to master every corner just because features are added. This is not true most of the time.
Of course you layer features on top of existing things. It is the only way to "simplify" the language and keep it compatible. For example, now you still have raw pointers: noone recommends managing raw memory anymore, the recommended thing is to return a smart pointer or do RAII inside your class (this last one pre-C++11).
How about virtual functions? Oh, now you have to know more (and this actually does not really hold true in every context, sometimes it is easier): of course you might need to know more! Recommendation is to mark with override! How about template metaprogramming with SFINAE! No! Hell, NO if you can avoid it! That is why constexpr, if constexpr and concepts exist!
It is not more difficult to program in the last standards, it is way easier to program. What is more difficult is that you need to know more. But you do not need to know absolutely every aspect of the language. They layered features that are more general so that you stop using the legacy ones, and that is an improvement inside the constraints of what C++ is allowed to do right now to keep it useful (compatibility).
If what you want is to learn to program in permutations of all styles, including the old ones, in C++ and in all kind of devices... I do not know people that are experts at all domains and levels of the stack, no matter the language you use. So again, you can use your subset.
> But what is happening is that the "Modern C++" proponents are using it willy-nilly everywhere (because "hey i never declared any stinking types in <scripting language>"). Similar arguments can be raised against a lot of other features.
You basically said nothing concrete above.
BTW, noone prevents you from using many of the inferior styles. And by inferior I do not mean non-modern, I do not buy modern for the sake of buying it, I use the features that make my life easier, and the same feature or library thing that makes my life easier in one context is the one I discard in another (for example dynamic memory in embedded or fancy ranges in videogames I might need to debug and understand to the vectorization loop level if I do not have the parallel algos).
You can still, as I told you in the comment above, ignore override, for example, and try the refactoring exercise I told you, making your life more difficult on your way.
Or ignore structured bindings in for loops and declare the variables yourself for pairs.
Or you can do some fancy metaprogramming with SFINAE and spend 3 hours figuring out what is going on or why you cannot use it in the parameter type of an overloaded operator and have to use it in its return type or guess which overload you are selecting, because if there are two difficult things in C++ those are initialization and overloading.
In the meantime, some of us will be using some concepts to constraint the overload set, or, even better, present as interface the weakest of the concept fullfilling a function and use if constexpr inside to choose the optimized paths for each type as needed.
Those are improvements, BIG improvements on how I write everyday C++ code. The language is big, bc there is not a choice. But a good training and taste for what to use and what not to use in your area of work is necessary.