Anyone have any advice for Arduino replacement? I recently (unknowingly) bought a R4 for some LED projects but knowing now the background, I'm wondering if there's any other alternative for hobby (noob level) micro controller project
For my work projects, I use Teensy because it's the screaming-est processor, and I use its computing power. The cost isn't exorbitant since it's typically re-usable unless you want to turn something into a permanent installation.
I suggest play with what you've got until you get sick of it, or run into a hardware need that would be better served by another processor or board. Or choose a new board when your R4 goes into something that you want to keep.
I've tried to maintain a "platform agnostic" approach, where I stick with the general Arduino API and processor-independent libraries as much as possible, and only drop down into the vendor-specific libraries when there's a real performance reason. This makes it easier to switch boards if needed -- a lifesaver during the chip shortage, and possibly important under present day supply chain uncertainty.
Doing it this way will give you the benefits of drawing from a broader range of tutorials and docs, while also providing a gentler learning curve on working with the low level chip-specific stuff.
Still can be reflashed if you have access to the right pins, but I believe there are more security features built into the later generations of these chips (plus some security fixed from the original 2350 design).