Guardians - Yep, the grind was real pre nerf of mats. 8 blueprints for 1 module! logfest galore!
engineers - Yes, the mats traders to help a bit.
Exploring - radio button simulator, really.
Combat - You can do without, but much more fun when pimped... start grinding.
I think they really got their game loops wrong. When game loops turn into mindless repetivness, then it's a grind.
Maybe not loot boxes, but loot to drop in general, like a good module that you need to take to an engineer to have it pimped. And it would have certain base stats that would be better than the stock modules anyone can buy. As an idea. People mind "grinding" less, if there is a chance of a good reward. Something exciting to drop. When you just keep blowing up rocks and crystals, you know exactly what's going to drop.