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