Someone painted this door with latex paint over oil based glossy paint, without proper surface preparation (*). Thus I'm left with some original oil gloss, and a edge to some still-stuck latex paint. Here it is after peeling, scraping, sanding and priming:
I sanded everything using EPA Lead Safe Practices, but the edge is still starkly visible, especially after the primer went on.
What are various methods and tradeoffs for making this edge disappear? This is a high touch area on the door, so it needs to be durable. Do I prime first? Spackle first? What product and steps should I use?
(*) Someone was Mom.