ffmpeg – concat stretching my video

When I use, force_original_aspect_ratio=decrease the video is centered. But when I use, force_original_aspect_ratio=increase only the height scales up to fit the screen. the width does not scale up and the video appears stretched.

Here is my code, and the video files I am using.

Example.bat

ffmpeg -i test1-.mp4 -r 30 -video_track_timescale 1000k -vf setsar=1 -q:v 1 -f mpegts -c:a copy test1.mp4
ffmpeg -i test3.mkv -r 30 -video_track_timescale 1000k -vf setsar=1 -q:v 1 -f mpegts -c:a copy test3.mp4
ffmpeg  -f concat -i mylist1.txt -vf scale=720:1280:force_original_aspect_ratio=increase,setsar=1 merged_video2.mp4

mylist1.txt

file test1.mp4
file test3.mp4

Video files
drive.google.com/drive/folders/14mBJ_RyA-Pw1W-eCKn4ujB9FQ6UPZ1Y-?usp=sharing

test3.mp4 is the video being stretched when using, force_original_aspect_ratio=increase. It has a custom aspect ratio (screen recording)