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