At most one ORM in active use

Two ORMs pointed at the same database produce split-brain writes: Prisma and Drizzle cache query results differently, generate non-equivalent SQL for identical model intent, and maintain independent connection pools that break transaction isolation. Concurrent writes through both clients can bypass each other's query-level constraints and leave rows in states neither ORM expected, corrupting production data and making debugging nearly impossible because neither stack trace sees the whole picture.

Pick one ORM and migrate every file off the other. Inventory the damage first with grep -rl "from '@prisma/client'" src/ and grep -rl "from 'drizzle-orm'" src/, then port the smaller side to the survivor. Once imports are zero, run npm uninstall drizzle-orm drizzle-kit (or the Prisma equivalent). If you genuinely need two databases, isolate each ORM to its own connection file like src/db/legacy-pg.ts and document the boundary so no future commit crosses it.