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