help: looking for the best headless cms to power an interactive abandoned building map (nextjs 13, sanity.io vs strapi)

lol so i'm trying to build this live map of derelict sites we explore on weekends. i want it to pull data from a cms that can handle geojson blobs, markdown notes, and image galleries without blowing up on cheap hosting. i've played with sanity.io because of its GROQ and real‑time preview, but the pricing model feels sketchy once i hit 10k docs. strapi is open source and looks solid, but the admin UI feels half‑baked and i’m not sure about its geo support. any other headless cms that play nice with nextjs 13 app router, have decent free tier, and can store large media assets? also if you know of any plugins or custom schemas for handling lat/long fields without writing a whole resolver, drop them. tbh i’m fine with self‑hosted if it means no vendor lock‑in, but i need something that won’t require a full db admin setup. suggestions appreciated, especially if you’ve actually used it on a map project or similar urban‑exploration site.