Game concept
Spiritual Fulfillment Level
The game also links it as Spiritual Fulfillment Levels.
From the game's encyclopedia
A Character's Spiritual Fulfillment is divided into Spiritual Fulfillment Levels by thresholds, each applying its own effects.
Low levels make life harder and sinful deeds cheaper. High levels make devotion easier and open new religious options.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Spiritual Fulfillment Level is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Character's Spiritual Fulfillment is divided into Spiritual Fulfillment Levels by thresholds, each applying its own effects." It is part of Spiritual Fulfillment. The game also links it as Spiritual Fulfillment Levels. Patch 1.20.1.2, from game/common/game_concepts/pam_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/pam_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.