1. A clear explanation of a symbol system and how math is a symbol system to deal with issues of quantity, shape, structure, and logic.
2. Frequently converting between diagrams/drawings and symbols (show "x x x" at times and "3" at other times). I actually have a concept for a game I want to program that does this.
3. Showing multiple concrete applications of different ideas, and lots of word problems. In retrospect I think this was always reversed in the American system. We would learn the symbolic and algorithmic aspects of a math concept, then use it to solve some word problems. Once I went back and started teaching myself some of this stuff, I read that the Russian system is quite the opposite: lots of word problems, multi-faceted problems. I suspect I would have learned from that style a lot better.
EDIT: One more point I should make. I scored in the 85th percentile on my SAT math. It is probably not a great sign for our system of education that I could do so well with nothing but the most rudimentary understanding of what I was doing.
Euclid II also develops most of Algebra geometrically, so there's much conversion between shape and symbol baked it. His method of computing the product of binomials is far superior to what's commonly taught.
So there's a good tradition of the thing you're looking for!
What you want is methodology like "just in time learning" or "problem based learning", which is very powerful but also very slow. You have to greatly reduce the content you can cover in a class. It's good for some students, boring for the smart ones (who solve your fancy word problems instantly), and the worst ones don't pay attention or do homework either way.
Asian education systems like India, China, Japan are very rigid and based on rote practice and memorization. "Prep school" there means evening schools where they just go do yet more memorization and rote practice to help pass entrance exams. Yet they produce many brilliant mathematicians too. Of course the students are motivated by parents and society, not love of cramming.
The ideal would be teaching that is individualized and does the best it can to get through to each student (there are plenty of efforts and even "edTech" that tries to do this, especially at lower grades). Without that it's always a trade-off in which students get the most value for the time spent.
I was "good at math" in high school, to the extent that I could crunch through any problem in the math or physics textbooks. School math existed mainly to serve the science and engineering students. Now I was happy to use math, for instance in my electronics and programming hobbies, but that wasn't math as an end unto itself.
But proofs are what really made math come alive for me. I don't think this makes me a freak. A lot of people I know from my generation said that their favorite high school math course was geometry, which was heavily proof oriented at the time.
Sadly, the contemporary K-12 math curriculum is sorely lacking in proofs.
Now, what about the students who would be more motivated by usefulness than by abstract theory? For those students, I suggest looking at how people in the so called "real world" actually do math, and work backwards from there. My days of abstract math are behind me, but I am still one of the "math people" at my workplace, in an industrial R&D department. When I do math, I'm never far from a computer. Yet school math is still taught by mainly pencil-and-paper methods, even if those have been translated to online forms.
For many of my math tasks, I start by playing with numbers, e.g., computing a function and graphing it in a Jupyter notebook. It brings tears to my eyes that K-12 students are not exposed to this. For one thing, it's fun, and it's an honest portrayal of how people actually work. For another, you can brute force your way through a problem even if you've forgotten some particular formula, making it more likely for someone to use it later on. Graphing calculators are of course a thing, but they hardly go far enough.
I think you're onto something, because teaching myself programming was precisely my backdoor into math. I remember a line in the Clause Shannon biography "A Mind at Play" that said he was essentially the same way: he wanted to apply his mathematics and understand the proofs/structure behind it, but essentially (as the title suggests) it was a form of play.