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