My d took French 3 at a university in the summer rather than taking another year at her high school. Not only did it go onto her high school transcript, but it also transferred directly to give her college credit when she got to college. Something to think about, since you can’t get college credit for high school language study until you get to AP in the fourth year. I think in-person classes are better for foreign languages, but if you’re planning to do an online class regardless, you might want to consider a university-based one in order to get both high school and college credit. One example: https://il.wisconsin.edu/catalog/course.aspx?course=U912-203
The lack of a “grade bump” is not a really good reason to cut short foreign language study… but if your HS doesn’t require another year of Spanish, you could theoretically take a college-level class (at community college or summer program or online) and just submit that transcript separately to colleges without having your HS add it to your transcript and GPA there.