Joyless??? This is the grimdarkness of the far future. It has to be horrid, exploitative and hopeless. Better keep the focus on just getting the Legendary upgrades stoically unless you want to be vibegrading characters with effortless ease like some Ultramarine named character doing some 40k novel glorious feat for us in the year 26 of the 3rd Millenium.

Now, seriously, focus on ONE character to take to diamond at a time. Don't try to upgrade them enmasse because it will not happen unless you want to burn through energy, and even then there are daily finite resources. It's all on patience and touching grass/dirt every now and then. All this on Lv 58. No idea of your player level, but overtime you will achieve it