I want to develop a mobile app with Cloud Firestore as backend. It's good until I realize need to implement FullTextSearch, and Firestore doesn't support it natively. Although they advise to use @{Algolia}|tool:589| but at this time I'm not willing to pay for it.

Therefore, I'm thinking about using the built-in tool from Google Cloud. Since this app is online-only, the offline & sync are not a top priority, so how about use Google Cloud SQL? Or, do you recommend any stack for me? Thanks for your advice.