1, 2 and 3/ -> no
in order to increase the %samples > rxqual 5, then you should actually keep your ho qual threshold at 4 or 4.5. If you put it to 5.5, then you’ll have more samples at rxqual > 5.
Anyway, that’s probably not the are we shuold be tuning right now, regarding your target.
AMR would increase the voice quality, but the rxqual stays identical.
Have you tried making your power control more aggressive ? Thanks to PC Thresholds : try to reduce the DL and UL tx powers in order to avoid interfering neighbours.
downtilt and azimth is a good approach. What is your average downtilt ?
Are you using electrical downtilt ? If you are using mechanical, then the benefits on interference are not so interesting : the backlobe and sidelobes are not downtilted !
Only the electrical tilt provides a good way to reduce intereference.
when doing drive-test, can you detect where are the interference coming from ? Try to work on a specific case, see if more downtilt or better PC would work. Also, think about using antennas with a vertical bandwidth which is narrower.
good luck 🙂