This isn’t explained in game, so I’ll give my suggestion for progression path that I know 100% works and a few people who have followed my advice are in the TR62/64 range already.
Current theater is designed around the expectation that players are TR60+. AKA Endgame.
TR1-50: Main Story and Side Quests.
TR50-55: Fill out noctoyager manual, collect one of every demon wedge in it.
TR55-60: Collect one of every character and one of every weapon you can, and ascend them to max lvl. (DO NOT do smelts or introns yet except for your favorites)
TR60-62: Reascend every character/weapon you just did previously to the new cap.
TR62+: Gold wedges. Introns. Smelts. Genie ascensions. Etc, etc, at this point efficiency is mostly out of the window and progress will become very slow, but you will have access to all of the best methods for things like gold/globs/lunos/etc now since you are over TR60.
For the TR55-60 path, Bounty/Chase can actually be a good option since it gives you globs, luno coins, and gold in fair amounts, and helps break up the gameplay from trying to do excavation or defense missions only.
Post TR60, Maze becomes the best source of gold, better than chase, better than excavation. You can get around 700k-900k gold in about 7-10 minutes using a 210% or 300% boost that you gain access to after TR60.
Additionally, because of Huxua’s launch, you can even push some of these numbers back since focusing the main story will get you even higher then TR50 now.