This took a while, but I finally switched over my domain from V1 (free) to V2 (trial + paid), and within a few days I got my first subscription customer! And just a few days ago their trial ended and got converted into paid subscription. At $19 MRR with the potential for churn, it's not much, but I'm really happy with my first steps!
react + firebase auth + firestore + bootstrap + google sheets API + stripe
I appreciate any constructive criticisms and suggestions!