IMO there aren't any. It's mostly about reading datasheets, and connecting pins to each other IOC those datasheets.
Maybe the physics and mathematics are more important for analog electronics or designing ASICS?
Do you have any specific projects you'd like to build? Post here and we can talk through it. And/or start by downloading KiCAD and clicking around until you understand the UI.
The programming side is mainly also reading datasheets. Instead of connecting the right pins together, you are writing a certain value to a register, as described in tables.
I'd previously had a barebones interest in electronics (think: kits with LEDs and buzzers in like 3rd grade), but listening to his discussions and explanations of how these things worked gave me a fairly decent understanding of how some basic electrical principles work.
I also recently watched a video series[1] that explained how microcontrollers (specifically the ATMega328, the one powering the Arduino) work, from a very low level that I've always wondered about. The key part of that series, for me anyway, was getting the chip off of the Arduino PCB and onto a bare breadboard. From there I went and read/skimmed the ATTiny85 datasheet[2] (a very popular "baby brother" chip to the ATMega328) which also helped me understand how these chips do things like PWM on a low level.
I've built one project (a simple PWM dimmer based on a potentiometer) and am working on another (designing a PCB with KiCAD[3] to replace the circuit board for a battery-powered LED lantern, so I can design my own sequencing interface for what happens when you press the singular button), and it has been quite the learning experience, but one I've greatly enjoyed!
[0] https://www.youtube.com/@bigclivedotcom, also at https://odysee.com/@bigclivedotcom:0d
[1] https://www.youtube.com/watch?v=tBq3sO1Z-7o&list=PLNyfXcjhOA...
[2] https://ww1.microchip.com/downloads/en/devicedoc/atmel-2586-...
[3] This comment is long enough already, but KiCAD is a fantastic piece of FOSS software. It's a full schematic/PCB design suite, and there are plenty of tutorials all across the Internet for it.
You can learn something practical like "embedded DisplayPort should be impedance controlled to 100 Ohms" without fully understanding the physics behind it.
AI can be very convincing. It told me to put the ESD protection as close the Ethernet connector as possible, so I put it between the port and the magnetics. This worked, but resulted in around 1% packet loss. When I moved it after the magnetics, I got 0% packet loss. This cost me a full revision, but I'd say this is the price to pay for not learning everything by the book.
For GP: this is something you would learn from a PHY manufacturer's EVK schematics and layouts. TI (especially), NXP, Microchip show correct magnetics/ESD part numbers and placement - the trickier thing here is finding an EVK that doesn't just use an integrated MagJack.
I've seen KiCAD running in the browser, so it's not like this isn't completely doable. It's just a question of resource allocation.