Its been a glaring issue with the last bracket for assault air arcade for years now. Perhaps only recently-ish exacerbated by the influx of agm65, kh29, etc that are able to nearly wipe entire groups of ai before anyone even gets close, especially lower tier jets.
We have submitted and suggested changes to try and improve on both assault modes as well as heli pve, but only to fall on deaf ears… sadly.
The issue isnt strictly lower end of bracket either, as with the higher you need to practically destroy almost all targets to get enough points to count remotely for activity at the end of the match… due to br difference between higher br aircraft and vs low br aircraft.
My only suggestion at this time, considering the lower end br aircraft you are using, is to stagger your waves opposite of the main group. By that, I mean stay back from a wave that majority of players are heading, and position yourself heading the opposite direction of which most likely the next wave will be appearing… it can be risky at first but you will see the pattern.
The only good thing about the lower end aircraft is that you dont nearly require as much kills for essential points to get activity for rewards…
Alternatively you could also learn of the spawn locations of artillery, so that you can position near those areas for when they spawn, although its a bit higher gamble as some players will instantly respawn once artillery pops up so they can sling bombs with higher aircraft.
We really need a complete overhaul of both assault modes, new maps, bracket changes to also include beyond 12.7… but i doubt we will see much of anything as we havent in the past, as previously mentioned.
Hopefully a bit of this info helps, best of luck o7