I've always read the interaction when he's chasing her as having subtle and not-so-subtle flirting on the behalf of Luthien (maybe not the BoLT one, if that's where she runs away scared. Too lazy to check rn). Giving Luthien agency is the important thing here. If she's leading him on, deliberately, and the audience can see she's clearly into it, then "rough man from the woods starved of female company chasing beautiful single girl" is not hopefully not the first thing that pops into people's minds. Having Beren happy to see an eruhin, any eruhin, not just a pretty woman, would tone down the stalker-ness of it all. And she could challenge him in some way that makes him stop and think, not sure what atm.
Also, speaking personally, my wife was, 20 years ago as a teenager, very much thinking Aragorn in Jackson's FotR better-looking than Legolas (and I'm no Legolas ;-). Luthien's been surrounded by pretty and/or superlative Elf dudes her whole life (Saeros, anyone? We are playing him as a dandy and/or a fop, iirc), it's a plausible trope to have her prefer something different. I suppose the whole Daeron dynamic is relevant here, but I can't recall how their relationship was framed in the past. "Just
On a different note, pixie cut Luthien after the treehouse scene? Thoughts?