i maybe got confused because i played it with bug knight mod too. maybe the relic is from this mod

so u need 5 on dream nail. this get frome events and kiling enemies on act 3 u shoud get radiance

I've tried many times and I never seem to get enough points on the dream nail, is there something I should do to make sure I get them?

So the (secret) is pretty straightforward, though probably really hard to actually notice. The Dream Nail does a bit of extra damage on the Heart at the start of the fight for each Essence you've acquired. (off the top of my head i think it's 10 per essence, it's not going to WIN the heart fight, but starting with an extra 50-100 damage is a really nice bump!)

This was originally a temporary thing. with the Dream Nail ending up being used in Act 4. As I was still planning on Making a Unique 4th Act, consisting of 4-5 of the Godhome Enemies (Sly, Nightmare King Grim, Absolute Radiance, Zote Swarm, and Perfect Vessel.) Unfortunately, the Godhome DLC's data is formatted very differently. Which ended up meaning that a lot of the way I manually remade each sprites animation wouldn't be able to be reused with the sprites. And that Ended up being unable to proceed.