There’s no real method of manipulating the system other than as below - but some BR’s are very popular - eg Tiger 1 tanks at 5.7 and 6.0.
So if you are just above that BR you have a good chance of getting a down tier (you are higher than them), but if you are just below that BR you have a good chance of getting an uptier - they are higher than you.
Check how matchmaking in Air Arcade works in the wiki - Matchmaking | War Thunder Wiki.
Yes that can happen - basically a player can have 1 aircraft at a BR point 1 above the nominal BR, as long as every other aircraft in your lineup is at least 2 BR points below the nominal.
So in your game BR range is 1.3 to 2.3 - you are at 1.3 - it sucks, it’ll get better.
However someone has brought a 2.7 plane, and to keep their BR to 2.3 every other aircraft in their lineup has to be 1.7 or lower - ie at least 2 BR points below 2.3.
When you get a 2.0 plane you can start doing it - run the 2.0 plane and have every other plane in your lineup 1.0 or reserve, and your BR will be 1.7
Often it is not worth doing it since a lineup with all aircraft at the same BR is generally much better than as single plane 1 above plus lots and lots 2 below.