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