Yes, there might be. There are many fan communities out there where fans create fanfics about different pairings. You can start by looking on popular fanfic websites like Archive of Our Own or FanFiction.net. Just search for 'soma love erina' and you may find some interesting reads.
Well, you can expect a lot of romantic elements. There might be descriptions of their growing feelings for each other. Maybe some sweet moments like shared glances or secret meetings. Also, the fanfic could explore how their relationship develops in different scenarios, perhaps in the context of the anime's setting or in some alternate universes.
One of the highly recommended ones might be 'A Taste of Love' which beautifully captures their relationship's growth. It delves deep into their emotions and how they come to understand their feelings for each other.
You can try some popular fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. They usually have a wide range of fanfictions, and you might be able to find ones related to Soma and Erina's love story there.
"My Husband is the Drug God" might meet your needs. The story is about a person named Han Qing who grew up in a laboratory and was used as an experimental subject. A chip was installed in her body. His father had been researching how to strengthen the A. I. Chip until one day, when Han Qing was discovered, he felt betrayed and hurt. I hope you like this fairy's recommendation. Muah ~😗