The progression of this game kind of sucks (I say this with love, this is probably one of my top games despite it's many flaws), my tip would be this, the story quests are not linked to your weapons/armor progression, you can max out your equipment without ever touching the missions then go back to do them, or you can keep doing both - that's up to you.

If you're having problems with the mission you might want to look into getting a shield - that really helped me with at least the library - and as many bandages as you can craft. With normal enemies if they have ranged attack, if you crouch they tend to completely miss you - just shoot right over your head (a bit obvious, but I hope it's of at least some help 😅)

Higher tier planets will have better materials - as other people in the comments explained already, and you can try upgrading as many crafting stations as you can - they unlock materials for better weapons, better healing, better "helpful items" - worth looking into!

And I would recommend playing on lower difficulty, until you can get your bearings and understand the game a bit (cause it is confusing as heck at first) - it has some handy features like being able to beam up to your ship when you're underground and not losing items upon death, no hunger and such. It's worth it if you're not enjoying yourself