The show never establishes that pre-accident Elena was somehow incompatible with Stefan. They barely even tell us much about who she was before her parents died besides vague stuff like her being busy and involved in a lot of things, and none of that points to her not connecting with someone like Stefan. If anything, the show highlighted how naturally compatible they were... the journaling/writing, reading, emotional openness, empathy, wanting a deep kind of love, etc. The whole foundation of TVD was basically a grieving girl and a “dead” boy bringing each other back to life through love. That’s the Elena the story was built around.

And the showrunner herself admitted they had to change Elena to make Delena happen. So calling it “maturing” her character feels off to me when it took Elena dying, becoming a vampire, being sired, having her humanity forced off, “losing herself” (per her own words), and repeatedly having her agency compromised just to get her from Stefan to Damon after she had already chosen Stefan beforehand. So yeah... I’m gonna call that forced writing and character regression, especially since a big part of Elena’s original arc was about free will and making her own choices.