Ok, not exactly clear what you're looking for
Getting a pretty simple STM32 board designed and functional shouldn't be that hard.
The Data Sheet does have a lot of detail.
Most people fail because they decide to skip basic things.
Do not wire up all supplies. Especially the Analogue one
Chose to leave off components and supplies they think are optional or inconvenient.
Don't connect BOOT0 to a pull-down.
Ignore VCAP pins and capacitors. Choosing random components, or nets.
If you follow sound design practices, the board should startup. Due diligence at the pin and netlist level is also important, go back to the original documents, not tables you've generated or had CubeMX generate along the way, basically close the circle. In IC design sending off a bad design is very expensive, so you check it a lot first, and then check it some more, and have others cross-check,
Adding more complicated external parts and interface, you're going to have to read more documentation. By "reference design" I'm assuming parts, driver sw, layout/signal path expectations. Across the STM32 boards and models there's a lot of working templates.
AdaFruit carries some of the Chinese board, though admittedly not the one you want
https://www.adafruit.com/product/5032
