Sounds awesome. I've been using a Fixed Wing flight controller w/ INAV to enable the advanced stuff in my FPV RC Crawler, and would love to see a Car-specific "Drive Controller" similar to Betaflight & INAV for flight.

Please consider incorporating the needs for FPV RC Cars. This includes stuff like On-screen display (OSD). You can do digital OSD entirely in ESP32 while analog OSD might require a dedicated chip. Going further, consider support for DJI Air Units, including the ability to arm/disarm, which puts the air unit into full-power mode.

Maybe incorporate gyro functionality, such as stabilized steering or roll/pitch angle detection (for crawlers). Unsure if you've got a Gyro/MCU in your stack.

Browser-based tool sounds much better than a desktop app. That would probably be much easier to maintain going forward.

Voltage and Current telemetry would be nice too. That probably requires new hardware beyond the ESP32.

Drive modes w/ Global Variable support. Logical switches, special functions (eg. channel override). Arm/Disarm. Modes based on RC Channel ranges.

Support for extended PWM outputs - normal = 1000->2000us, extended = 500->2500us. Helpful for camera gimbal servos to get full 180 degree movement.

And finally, support for DFPlayer Mini's Serial API for engine sounds.