Hint: if your product plans involve a raspberry pi, you probably fucked up.
It's more common in the pre-built devices to have a controller that's using a main CPU plus a FPGA or CPLD. The better hobbyist drivers use things like a beaglebone black and it's onboard "PRU" that can drive real time from memory it shares with the ARM cpu and Linux.
Also, since it's pulling train data, you need more smarts or cycles than a typical MCU to pull via WiFi/https, transform text into pixmaps, etc. Though there are examples of beefy MCUs doing all this well, like an ESP32. Or examples of small MCUs driving a small single color matrix.
Edit: Yes, you could even use an ESP8266, though 32x128x3 plus X bits of PWM brightness would mean being limited to drawing from storage rather than in-memory manipulation. I'd jump right to the WROOM type devices with PSRAM.
It's fine for prototype at a very early stage, absolutely not fine for something you ship to a user.
Am assuming here that they're adopting strategies to minimize/work around the problems you mention.
An integrated combination or even a board design offering from either of the two mentioned manufacturers would be awesome and really help bring down the barrier to entry for hobbyists that want to try moonlighting as entrepreneurs
Hardware academy is also good, where you can ask questions and meet other folks who build electronics products.
https://predictabledesigns.com/academy/
Happy to talk and give pointers, email in my profile.
Edit: I've no affiliation with hardware academy
However, for small-quantity, high-quality PCBs at a great price, once you have the design done, it's hard to beat OSHPark and OSHStencils for solder stencils. I highly recommend both.