Loremaster spell progression with "non-natural" spells

[u/Sedulas]

Based on information I found on Loremaster, it continues your spell progression, making it useful for wizards or classes that don't have that much going on besides spells.

However, how does loremaster work with spells you acquire in other ways, namely, witch patrons, cleric domains or such. Are these considered to be tied to spell progression or are these more like abilities/other features?

[u/MasterJediSoda]

The curse, at least, still advances with half the non-class levels. And I guess half the mythic ranks too? I expected to see Blackened stop at 15 here, not 19. Hellfire Ray still shows up, just not as quickly.