Spinning an IMXRT1062/IMXRT1064 design sans the terrible Teensy bootloader should take a day or two at most.
These chips have perfectly-fine ROM USB bootloaders and SWD, don't ruin them by adding extra garbage.
The layout of the Teensy 4.x was challenging as I recall with the speeds involved. But maybe you are a demigod of compact high clock designs.
The layout of the Teensy 4.x was challenging as I recall with the speeds involved. But maybe you are a demigod of compact high clock designs.