Merge multiple video files using ffmpeg by adding multiple compress options
All filtering should be performed in the same filtergraph. Each -filter_complex or -vf defines a different filtergraph. You can use

-filter_complex "[0:v] [1:v] [2:v] [3:v] [4:v] [5:v] [6:v] [7:v] [8:v]  [9:v]  [10:v] concat=n=11:v=1,scale=1280:720,setpts=0.20*PTS [v]"