I have excelent experience with both NANO PI and STM32.
I have worked with many Single Board Computers (SBC) like Orange pi, Nano pi, raspberry pi, Udoo, Hikey960, Tiny Rex, Beagle board black, Beagle Board X115, T113S3 and Nivida Jetson. I have used Nano PI and Nano Pi Neo in different projects. I used it in Serial communication to control Radio Rigs, RS458 to collect data from different nodes and there was HMI LCD and also it rovides SNMP for the different nodes,....
I have used many cameras before with different SBC, I used MIPI Camera with Nvidia Jetson with serdes links and I used analog thermal cameras before with T113-S3.
I used thermal cameras before with STM32 and MAX7456, to write on the video output of camera some data.
I have also excellent experience with STM32, I have worked with many families of STM32 like STM32F103, STM32F205, STM32F407, STM32F415, STM32F429, STM32F446, STM32F469, STM32F769, STM32L562, STM32L432, STM32U575. So, I have no problems with STM32 and I used many IDEs with STM32 Keil, IAR, STM32Cube IDE, Eclipse, Visual Studio Code and Arduino.
I can also do the PCB considering the PCB cost. but keep in mind that the project key isn't the PCB, it is the FW.
I also own great debugging tools for both HW and FW (Fluke Oscilloscope, Logic Analyzer, Segger Trace, Segger PRO), these debuggin make life more easier with development.
If you want we can have more discussion about the camer output and the whole project.
Thanks in advance