True, but actually I have a very hot take rant on this. The problem isn't that people don't know how to write romance, it's that society sucks and brainwashes people into thinking that romantic relationships (and to a lesser extent, having kids) are the end-all be-all. Now, this may be a chicken or egg problem - is the oversaturation of romance in media influencing society? OR is society over-emphasizing marriage and kids influencing media? Well, I will say considering some historical traditions that rely on the marriage aspect, I'm going to guess the latter, but feel free to argue the former.
Maybe it's because lately I have been hounded by a good chunk of people in my life about why I am still single and not looking for a relationship at my age, so I probably have a special hatred for most romance writing currently born of my annoying circumstances.
There are people who aren't suited for a romantic relationship at their stage of life, but due to societal pressures are led to believe they need one to solve their life's problems. How many instances do we see the bad joke about a man hating his wife? Or a woman complaining about their lazy incompetent husband? It makes me think if society never elevated romantic relationships to these people, these kinds of people would probably be living happier lives fulfilling the goals they need to fulfill. On the flip side, you would have people proclaiming they will do anything for their best friend, "Bros before hoes" kind of stuff. In fact, complaining about their partner is something most people do with their friends.
Why do I bring up this real-life issue in relation to romance in fiction? Because I believe that because society paints romantic relationships as "important task to fulfill" in life, most writers end up just having a rigid view of how people behave in romance. It should have the typical kissing, loud proclamations of "I love you", physical intimacy. But they never get into the nitty gritty dynamics of the relationship. How the two characters in a relationship will behave around each other, other than your typical lovey-dovey behaviors like kissing, nicknames, saying I will die for you or something, or, if you want to get a little spicy, maybe add some snark in there (which doesn't matter because they are also snarky around everyone else). If you want to push the spicy envelope a bit more, we can get borderline abusive to full on abusive
I feel that most romantic couples in stories end up turning into this in the endgame. Is this reflective of real life romance? Well, I can't say, I've never been in one, but it's definitely quite boring to read for me.
Now why do I bring up the friends angle in my real life issue? It's because ironically, you'll find often in shipping culture that the fans end up not shipping the main (heterenormative) canon couple, but the MC and his best friend. Other than the desire for more lgbt representation, I think there is more to it than that that this tendency happens. I find that in most stories, the dynamic between the (male) MC and his friend a lot more interesting than the dynamic he has with his love interest.
Unbound by the expected normal behavior of romance, writers can explore behaviors and interactions beyond your typical blushing and kissing. Differences end up causing more high-stakes conflicts, because you're not saddled with the expectation that things will magically work out in the end. (A tendency I find in a lot of romance stories is that no matter how toxic, conflict-ridden a relationship will be, it will almost always end up becoming magically resolved at the end, supposedly seen as a "triumph" of overcoming troubles as a couple). Differences in philosophy can end up becoming a big breaking point between friends, and you become invested in how the writer will carry out this conflict, if it will be resolved or be broken beyond repair. How many times have you seen a romantic couple seriously tackling conflicting life philosophies to the point that it might break their relationship?
You brought up your issue with the "Enemies to Lovers" trope, but I think an even more glaring issue is that usually when this trope is used, the two characters aren't truly "Enemies" on a mutual level philosophical level. It's usually in a one-sided way where one character is "convinced" to another character's side. Oh how I would love to read an actual "Enemies to Lovers" story where two characters are in a constant fight to the death over their differing views, but slowly start to reconcile to something in the middle in their stream of never-ending conflicts, or even that the conflict twists their views to start to see the other POV. It sounds like a good challenge for a writer that I'd like to see someone pull off.
Another trope to rant about that I think is caused by society's over-emphasis on romance. Is the use of romantic relationships as a measuring stick of a character's growth. I'm looking at YOU, Jobless Reincarnation. So many stories focusing on the "redemption" of the character end up falling to a romantic relationship the MC cultivates as a way to say "look! MC has a girlfriend! He's healthy now!" While this could be an indication of character growth, I HATE the type of message these stories imply. That your journey to self-improvement is ultimately all a goal for you to "get the girl". Why do you think we get so many instances these days about incels whining about how they can't get a girlfriend despite going to the gym all day and building up their muscles?
All this to say, the failing of romance in stories is not just a writing issue, but also an issue that most people don't know what a romantic relationship even is and only parrot the pressures and media they consume around them about romance being about kissing and that it's super important. Even in this day and age, there are people who don't know the difference between romantic and sexual attraction and often conflate the two. And most people can't get it into their heads that a romantic relationships doesn't have to be the most important thing in their lives, that the harsh reality is that their "romantic partner" isn't so much a partner more than a person you used to fulfill a life checkbox, if you're just going to go behind their back and talk smack about them to your friends, friends that you seem to care more about but will never admit it because society has made you downplay platonic relationships.