How to get off to a good start with a legendary eval board

It was the board where ethernet, SDIO and CAN were basically unusable, and you had a handful of ADC inputs.

HAL/Cube is the newer, thicker, abstraction layer and robot code generator. It uses a paradigm that doesn't fit how a lot of us do things, it is just too bulky and frequently gets in its own way. Lot of unstated rules and expectations, easy to get into race conditions or priority inversions. While the code quality has improved (Microsoft/Adobe Style) there are a lot of regression issues, and stuff really isn't solidly tested in real-world application. So its good to get a quick demo to show off some feature, but practically you'd need to commit to a specific release and test the snot out of it in your specific application in a commercial product.

Most of us prefer the original SPL (Standard Peripheral Library) which has a 10+ year linage in to parts prior to the STM32, or more brutal direct register manipulation. I lean toward the SPL, but will switch horses where it serves my goals, and getting a workable demonstration running quickly.

Of the F4 board the NUCLEO-144 is the most open (break out board), and there are ones with Ethernet on-board, and SD/MMC sockets can be wired easily.

If Cortex-M4 (CM4) suits your needs, look at the newer L4 or L4+ families.

A lot of the DISCO boards will now take Arduino shields, and this is the primary route to add functionality, as the boards themselves soak up pins for LCD, SDRAM, QSPI, SDMMC etc.

The STM32F746G-DISCO has a lot of functionality, the CM7 used only has a single-precision (32-bit float) FPU.

The STM32F769I-DISCO has a much better screen (can drive HDMI panels too), and a CM7 with a full FPU with single and double precision, and you can power it using PoE.

The STM32F469I-DISCO is a CM4 with a similar screen but lacks Ethernet.

For WiFi perhaps the L475-DISCO IOT board

https://www.st.com/en/evaluation-tools/b-l475e-iot01a.html

For Cellular perhaps something with an STMod+ connector

https://www.st.com/en/evaluation-tools/p-l496g-cell02.html

Cellular, GPS or WiFi on Shields is also a practical method to extend the base functionality of the board.

Unfortunately there are a lot of choices, it is usually a balance of what key hardware the board comes with vs what is simple/desirable to add.

>>Feel like such and idiot here, especially for someone who developed and patented a product that is still running in the field in commercial use 10 years later 

Well I can subscribe to that, I like to make things bullet-proof so my phone doesn't ring with angry customers or support techs with pitch forks and torches. Which is why I don't care for the debris field development process Microsoft pioneered (rolling list of bugs, things that get fixed, things that never get fixed, new bugs and dependencies).