Trying to encode multiple audio files and map them to specific channels with FFmpeg

I have a video file(V1) and two stereo audio files(A1 & A2). I'm trying to output a movie with the video content and duration from V1, and I want to set A1's audio to the left channel and A2's audio to the right channel, even if those sources are originally stereo.

I've been playing around with the stereotools and pan filters but I'm honestly having trouble deciphering the documentation. Any help is appreciated.