You are on the right track. The cheap 8x8 matrix panels using WS2812B or similar LEDs are really just a string of LEDs arranged in a grid. An 8x8 WS2812B LED matrix just has power, data, and ground, just like an LED strip. HUB75 LED matrix panels are a different animal. HUB75 LED matrix panels can be loosely grouped into three generations based on complexity.
Gen-1: Basic HUB75 panels using 4–5 address lines, simple driver chips (ICN2037BP, FM6124), and separate row decoder chips (like 74HC138 or FM6124A). These panels are compatible with the Adafruit MatrixPortal S3, RP2040, and Adafruit libraries.
Gen-2: Panels with smart driver chips (like ICND2038S or ICND2153) that handle internal row multiplexing and require initialization sequences. These may use fewer address lines and are not compatible with most simple microcontroller libraries without modifications. There are some great libraries on Github that provide control of these panels using an Raspberry Pi controller.
Gen-3: Advanced grayscale panels using chips like MBI5153 or ICND2153 that support PWM or stacked PWM (S-PWM) for high refresh rates and deep color. These require precise signal timing and are typically driven with FPGAs or heavily modified firmware. Some GitHub projects have figured out how to support these.
Here are some sites that provide more info: