So, 'best' is gonna depend entirely on what kind of tension you're after. I've spent way too much hours scrolling through older Reylo works on AO3, and some of the most electric ones play with the Force bond as this constant, intimate violation—they can't block each other out, they're forced to witness private moments, and the resentment-fueled attraction is just chef's kiss. A specific author, 'diasterisms', used to write stuff that really nailed that push-pull, though I can't recall if those were explicit or more mature-rated.
Honestly, the real tension often fizzles in the actual lemony scenes if the build-up isn't there. I'd skip anything tagged 'PWP' if you want the slow burn. Look for longer fics where the rating eventually climbs to 'Explicit', and check the comments for people screaming about the 'will they/won't they' phase. The old 'Star Wars: The Old Republic' fandom also had some surprisingly good Sith/Jedi dynamics with a proper enemies-to-lovers arc.