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