There's a tech scribe guy in the Waystation in Shem. You can give him the notes for money and rep, be warned they don't disappear from your inventory though.

I couldn't find him! Not in the Waystation east of Black desert city. I'm confused. In that city there is a guy at the bar who wants a huge amount of money instead of buying them. I don't know what I'm doing wrong

Keep looking for a place called Waystation [Tech Scribes]. It's close to Flats Lagoon and not near the deadlands/that city. You're looking for a well dressed skeleton called Enrico in the bar.

I finally got around to this Deep Ore technology, having ignored it in every other playthrough.

Was a bit confused how it works and where to attain the research artefacts. It's a pretty cool system he has implemented, though I didn't much feel like going back to all the treasure sites I already visited just for the notes, which I previously thought was fluff content.

In the end I just rigged the dialogue so that you can buy your way into his shop through donations/bribes. Would rather pay 150k than to go around the world for those notes lol.