Many STB's underlying Android versions are based on Android mobile versions written for phones and tablets.
Good STB's will be based on the Android TV o/s versions.
This may be what is the root of your problems.
Try force android TV mode
to much work for apk
I found that no mouse is needed with ..........Mobdro......Teatv....Beetv.....Typhoon Tv.......... FreeFlix..HQ...........they work very normal.....only tried them in Buzztv 2000..3000...3900...3100.... dont have a 4000 yet
i never use mouse for 3900 too and why no use filelink to get all latest apks