If you wake up after 4-5 hours of sleep & find it hard to go back...

open.spotify.com/album/0B67pFtY…
Mag Threonate (or Bisglycinate)
Apigenin or,
If you’re peptide brave: pinealon (from a MD!); wow REM increase.
Into Rx approaches?: the new DORAS/Orexin antagonists: expensive but they seem to preserve/enhance REM.