Does this one have the JTAG/SWD pins available? I know that the teensy bootloader is one of its USPs, but not being able to connect a debugger is kind of a dealbreaker for any sort of complex project.
Many Arduino compatible boards support hardware debugging. For example the Adafruit Feather series have connectors for a J-Link debugger. The Arduino Nano 33 BLE and Sense have pads on the botom to solder the leads of a J-Link cable. STM Nucleos even have the debug probe built in accessible over the same USB port.
PlatformIO https://platformio.org/ is the preferred Arduino IDE (a plugin for VS Code). It has support for hardware debugging, C++ code highlighting, code completion and Intellisense.
Yeah this is why I have 4 of the last revision sitting in a bag on a shelf. I got tired of print debugging, if you look in the forums there is some discussion on how to modify the hardware, but it is not easy.
This has been a longstanding issue with all of the ARM-based Teensy boards, and it's really the main reason I'd hesitate to recommend them.