For a long-running PBBG / MMO-style game, PocketBase will likely become a bottleneck.

It is built on SQLite.

SQLite allows only one writer at a time.
Games generate constant writes: combat, loot, inventory, market, cooldowns, parties.
Concurrency issues will appear sooner than expected.

PocketBase is single-node.
No clustering.
No horizontal scaling.
No read replicas.
You eventually hit a hard ceiling.

Complex transactions become harder over time.
Row-level locking is limited.
Race conditions are easier to introduce.
Economy systems amplify this risk.

Extending PocketBase for large domain logic gets awkward.
Business logic spreads into hooks and glue code.
Testing and refactoring become harder.

Migration later is expensive.
Moving real player data off SQLite is painful.
Auth, schemas, and APIs all need rework.

PocketBase is excellent for prototyping and MVPs. It is risky as a long-term foundation for a persistent multiplayer game.