Thank you!
Well the good news is, I have most of their background, how they met, and details of it planned out. They have been friends for decades, but focus on outside things (growing up, careers, life goals, life paths, etc). So I don't have to worry about making a meetcute moment and worrying if it's too cheesy or evokes instalove vibes.
I wanted to tell a story mostly about how we all deserve love, even--or especially-- when we are in our most unloveable state, and the general "rom com" pattern does still kinda work for me (they meet, romantic tension is had, they separate because of conflict, reflect on causes of conflict and individual emotions, they reunite) but I didn't want the story to feel like something Hallmark or Lifetime would air, so it's good to keep in mind what you said.
As far as character development goes, that's something I zeroed in on first, when making them. Because their flaws help not only make them real, but also can drive, cause, or support conflict which is a good tool, I think. It's not so much giving them flaws that is my issue, it's being consistent with those flaws across the board, especially when they are flaws that are opposite of mine and I don't naturally understand them. I think balance is a good thing to keep in mind because I certainly don't want to put either of them in an abusive relationship with each other or with themselves!
That's also the reason I wanted to carefully portray the "best friends to lovers" trope, because normally it involves the guy friend only realizing his crush on his female best friend when another guy is interested in her and he suddenly becomes jealous... which isn't abnormal, but it isn't healthy either and shouldn't be glorified. It can easily turn into a "if I can't have you, no one can!" scenario which is incredibly abusive. So I've been working to avoid that as much as possible, making physical separation their wake up call, vs jealousy. But I forgot that how they interact can also imply abusive traits, if I'm not careful in portraying their interactions correctly.
And I think I'll have to play with their interactions more and see how they can tease and push and pull each other, but in healthy and fun ways. They are both very playful, so I think I have a lot to work with.
Thankfully, I am forced to give them individual lives and personalities because I wanted that to be the reason they never considered dating or mating in the first place. They've kind of known each other forever, but have been too distracted by so many other things to really notice one another that way. That being said, once they do reach that point, I can see myself easily falling into that trap and solely focusing on their couple-ness... so I want to keep myself disciplined with that.
Thank you for your advice! You've reminded me of some important things I need to to keep in mind to make this work.