

That’s a version of decadence, and I got what you meant originally, but most speakers in the north (well, United States, Wales, and Toronto, Ontario as those are who I talk to most) think more of the excessive indulgence stemming from moral decline.
“Oh that chocolate was so decadent” meaning “I feel like I slipped into gluttony and sin eating it it was so good”.
It’s kind of used as a mix between the two definitions depending on the context. It’s so interesting how language changes from place to place.
To be fair, that long ago the Internet felt like nothing but flash videos and flash games