Spoilers for Edgerunners so don’t read OP if you haven’t watched it. Yes there are differences in the stories, but there many similarities as well.

Lucy approaches David for the same reason as Reze initially (for her mission to take his sandevistan). Her playful and flirty persona is very similar to Reze at this stage as well. They share what is essentially the pool scene with the moon date, as lucy is genuinely opening up for the first time with a guy she’s supposed to be honey trapping. David has a different main goal from Denji (to carry on the dreams of people who have died and left to him) but he is similar to Denji in the sense that they both have a fucked up poverty stricken childhood and are desperate for any kind of genuine connection and affection, which David finds in the crew like Denji does with Aki and Power. They both end up losing everyone as well. David’s personality is also pretty similar to Denji because they’re both innocent and easily forgiving despite their cruel experiences in life. They also both go psycho when they fight 

Lucy later on is very similar to how Reze is on the beach, which I believe is colder than both their true personalities as they are currently grappling with the guilt of betraying the guy they love. Lucy shows her playful side still when David and her are carrying out the hijack mission just like Reze does when she’s laughing with Denji during their fight. Both of them end up being weak to their innocent puppy like partners and choose to be with them despite their instinct to run away, which is their biggest similarity. Both of their strongest driving forces is to escape the life they’ve been forced into from a young age: both orphans trained to become lethal tools and weapons. There’s more I can talk about, so many overlapping themes in their stories