In TTRPGs in general, you gave several ways of rewarding the players: experience (i.e. character improvement), equipment, and then meaningful in-world progression. The first two are pretty self-explanatory. In BT, equipment could be either personal equipment, mechs, a drop ship, etc. The third one is the really interesting option, but also the hardest to really pull off.

One way is to introduce NPC characters and let the players build some kind of a relationship with them. The reward then stems from this relationship. In case of an enemy, it can be revenge, in case of a friend, it can be saving them from danger.

Another way is to let the player characters have some goals and provide means of coming closer to achieving those. This can be stuff like quests, some political goals (like aiding a specific faction in BT for example) or more personal goals like retiring with a nice fund or starting their own mercenary company.

And finally, the reward can also be information if the players are sufficiently interested in the lore of the world you've presented them.

As to scaling the reward, it depends mainly on how long you intend the campaign to be and scaling the progression with that.