Reading the numbers
Integrated LUFS is the one streaming platforms act on: Spotify and YouTube normalize to about −14, Apple Music −16. A louder master is simply turned down - so judge your number against the platform table and strategy in the streaming loudness guide rather than chasing a target. True peak is the delivery spec that actually matters: keep it at or below −1 dBTP so lossy encoders don't push it into clipping.
The gap between short-term max and integrated loudness is a rough dynamics read: 2-3 LU means a consistently dense master, 6+ LU means real light and shade. Neither is wrong - genre decides. For the electrical side of the dB zoo (dBu, dBV, ratios), see the dB converter.