Arduino ecosystem is way to go for learning (and seriuous "non production" projects). I wish there would have been such when I was learning the ropes (or even interpret basics consoles etc. which now are again found after some 10..20 year hibernation).
In my opinion you need to differentiate two different layers of systems. The layer where many tote the C-language family, that is the control electronics hardware layer, where all the heap and other memory wanking "REAL programming" happens, in this layer your system knowledge focus is inward to uCUs and chips or computer internals. Second layer is the operational layer of system where your focus is outwards, how the environment and process you need to operate will behave. Your system knowledge is therefore not in the control device hardware (not only), but on instrumentation, logic, chemistry, physics etc. in this level you do not want to be heap wanking the memory etc. real programmers do that, but have full freedom (timely) to design and implement the contol of external things without the need to invest a huge amount to babysit the controller system itself. This dualism is not separation between Ie. object orientation vs procedural language, but general focus and abstraction of tasks.
Mentioned Forth is harder to start with and is niche language for certain fields (some exposure to it might not be a bad thing as it is so different), ie. in space exploration due to its nature of on-fly (re-)programmability as hybrid compiled & interpreted RTOS&program model, it was (is?) also used in some firmware layers.
All that said, I wish there would have been Arduino available, when I did ask same type of questions.
Tl:dr There is no such thing as "real programmers", closest to that do get computer scientist, but internet knows that those usually are wrong and are not true real programmers.