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