Does it have to be a novel? Some fantastic romance is being written in serialized form on platforms like Kindle Vella or Radish. You purchase coins to unlock episodes legally. It's a different consumption model—more like binge-watching a TV show—but the content is original, professional, and licensed. You're downloading episodes within the app. It's a cool way to follow a story in real-time and interact with other readers in the comments.
If you're academically inclined, sometimes university libraries have subscriptions to digital literature databases that include contemporary popular fiction. It's a long shot, but you might get licensed PDF access through an institution. For the general public, though, the path is commercial ebook stores or public library lending. The academic route is for very specific research purposes.
Honestly, just go to Amazon and search 'romance ebooks free.' Then sort by 'Publication Date' to see the newest free offerings. Indies run free promotions all the time to boost visibility. The descriptions and reviews are right there. You can 'buy' the book for $0.00 and it lands in your Kindle library. It's the lowest-effort, highest-reward method I've found for building a personal free collection.