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