Ok I normally level my aircraft using Assault Air Arcade because I mainly play Ground Realistic Battles and leveling aircraft in that just takes forever. But, once I get around the BR 5.0 level, it takes forever to get a group. Personally, I’d be happy if I could go it alone if there was reduced incoming wave numbers. Perhaps for every five minutes you wait, the amount of players needed drops by one and the numbers in each wave drop. That way you don’t wait in a queue for fifty minutes and still cancel.
Adding to this, BRs have increased by almost 4.0 (!) since they released this mode and half a decade later Gaijin hasn’t bothered implementing additional BR brackets beyond 6.3. Doing so would likely pull more players in as currently there’s no point in playing beyond 6.3 with anything other than supersonic radar slinging missile jets. I have a lot of Rank 5 and 6 jets I’m spading where unlocking several mods in PvE before jumping into ARB would be very helpful.
At 5.0 you might be better off finding a SB EC battle or if you only use a mouse/kb (and don’t want to relearn to fly) use ARB.
I have issues getting started sometimes with top tier and I have found that if you just stop after about 5 seconds and start the search again, over and over until you join a match, you get better results (This could be a Placebo effect but I still do it).