Betrayal Rewards in High Tier Maps

There are a lot of people complaining about Betrayal Encounters being to strong.
If you compare them to red beasts for example, they tend to be a little more rippy but not much harder to beat.

I am fine with how hard the encounters are, however i think that the current system is not rewarding at all to play high tier maps.
For Delve for example the sulphite spawns in higher tier maps reward more sulphite, so it is better to do the harder content if you want more rewards.

For betrayal rewards in safehouses (scarabs etc.) the most effective strategy is farming low level maps that can be run super fast so you just get alot of encounters.
This system rewards fast map clearance, but is not good in terms of risk/reward of this encounter.
So i would really like higher level encounters to
a) Drop better/more items
b) Give better choices/more rewards in the Syndicate overlay. For example chances to get a scarab increase etc.

I would not prefer strong crafting options to be unlocked by unveiling only iLvl 84+ items for example, because if they are to common they are worth nothing and if they are rare people who get them have a rng money printing press.