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