If you lose against somebody with a lower rank than you the points you lose are higher, the same if you beat somebody else with an higher rank than you they are

It's not possible, only the whales are capable of doing so. Just like how arena is set up, if you play in one region (let's say NY), then you can have players from s1 be playing against s1000 just because of how it is set up. Oasis/Tencent has to limit the servers only to your sage brackets in order for better matching to occur if they want more ppl to have 6 paths in bonds.

*it's so easy now to reach 6 paths in arena.

Fixed.

There's currently only two ways to reach sage of 6 paths rank in DB.

1) be a whale. Like, 300k+ at minimum.

2) get help from a whale. a 400k running edo hiruzen is usually enough to beat under-300k's, and a 350k+ running a solid team (6p or bt kakuzu) can get you wins against 300k's. Ofc this depends on your own power; if you're barely 100k then the whale's gonna be doing a 1v2 against 300k's (300k is the 'average' player you're gonna end up facing; if you can't face 300k's and win, then you're probably gonna get a net loss or just stay put at your current rank).