Dex and Daredevil identity

I know Fisk finds out in Season 3 and then tries to paint Matt as one who has done his criminal bidding for Fisk to get the FBI to go after him. But Fisk keeps his secret identity to himself. Then Dex pretends to be Daredevil. I just rewatched it as well as keeping up with the new DDBA season 2 and I don’t think I notice a specific instance in OG season 3. Is it implied that it happened off screen?

I also just rewatched BA S1 Episode 8 and I’m just so confused. I’m assuming that Dex knows but I’m honestly not sure. Matt slams his head knowing it will loosen a tooth which is all he needed to escape? Is that implied between both of them that he knew why he did that and that’s why he said “thank you counselor.” But does Dex know he’s Daredevil at that point? Cuz couldn’t that play out the same way with JUST Matt Murdock the lawyer?

I need someone smarter than me to help me make sense of this please and thank you.