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