Here is the full list of all 38 Returnal achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Collect all main Achievements
Complete a daily challenge in Simulation Mode
Gain a moment of peace
Open the Locked Door
Finish Abyssal Scar Survey
Kill 100 Hostiles with Disgorgers
Finish Fractured Wastes Survey
Defeat Algos' final form
Complete the first Hospital sequence
Die and return in the Tower
Defeat Algos' first form
Finish Crimson Wastes Survey
Finish Derelict Citadel Survey
Finish Overgrown Ruins Survey
Finish Act 3
Finish Echoing Ruins Survey
Complete all House sequences
Finish Calculated Risk
Finish Act 2
Defeat Ophion
Achieve Weapon Proficiency level 30
Defeat Hyperion
Finish Act 1
Defeat Nemesis
Complete the first House sequence
Achieve 200% Max Integrity
Complete a Xeno-archive set (excluding Tower of Sisyphus)
Defeat Ixion
Returned by an Artifact
Defeat Phrike
Unlock all translation tiers of a Xenoglyph
Retrieve 10 Scout Logs
Have 5 Parasites simultaneously
Perform 5 successful Overloads in a row
Learn the basics of survival on Atropos
Achieve maximum Adrenaline Level
Scan a Xenoglyph
Experience a new cycle after death