Here is the full list of all 50 Starfield achievements. It takes around 100-120 hours to unlock all of the achievements on Windows.
Complete "One Giant Leap"
Collect 20 Quantum Essence
Reach Level 100
Complete "Entangled"
Complete "Unearthed"
Visit all Star Systems
Land on 100 Planets
Complete "Legacy's End"
Complete "The Best There Is"
Gather 500 Organic Resources
Join the Crimson Fleet
Reach Maximum Relationship Level with a Companion
Complete "In Their Footsteps"
Collect 10 Ships
Complete "High Price to Pay"
Complete "Further Into the Unknown"
Complete "All That Money Can Buy"
Gather 500 Inorganic Resources
Recruit 10 Separate Companions
Complete 30 Activities
Read 20 Skill Magazines
Eliminate 300 Creatures
Complete "The Hammer Falls"
Complete "Surgical Strike"
Join the Freestar Rangers
Complete "Into the Unknown"
Craft 100 Items
Mod 50 Weapons
Successfully Smuggle Contraband
Connect 5 Outposts with Cargo Links
Complete "Executive Level"
Eliminate 300 Human Enemies
Complete "Guilty Parties"
Reach Level 50
Join Ryujin Industries
Produce 500 Total Resources from Outposts
Visit 20 Star Systems
Complete "A Legacy Forged"
Complete 30 Terminal or Misc. Missions
Complete "The Devils You Know"
Reach Level 25
Access 50 Computers
Modify a Ship
Bypass 50 Digital Locks
Join the UC Vanguard
Reach Level 10
Join Constellation
Reach Level 5
Build an Outpost
Enter Space for the First Time