There might be some issues with worldgen not correctly applying. This need further investigation.

Was just about to open an issue for this to move it out of discord, im daedreus.
affected mods.
mythic metal;s 0.17.0 1.19.3
tech reborn 5.5.0
was asked to run /place feature while underground, doesnt seem to do anything

Banglum fails entirely
Adamantites the only thing that doesnt reply with "failed to place feature"

I tried Fabric 0.17.0 1.19.3 version, I faced the same situation. Ores are not formed. Will this be fixed with the next update?

Fabric API is to blame

0.73.3 added some world gen helpers, but appearntly forgot to mention them in the release changelogs

Ore generation works just fine on 0.73.0

Fixed in 0.17.1+1.19.3