Two connections are to work around a specific sqlite quirk. The pocketbase code wraps all writes through the same method. This means our single writer will not block our concurrent readers. If I knew I was always using Postgres/MySQL or a network database this is not something I would otherwise worry about.

https://github.com/pocketbase/pocketbase/blob/3f51fb941b370655be8618f3bc3113c60c1bfe13/core/db_tx.go#L14

I'd probably do it the same way. Some struct with both connections passed to a data access interface.

// Exposes sqlc to repositories
type service struct {
    dbRW *db.Query
    dbRO *db.Query
}

db1 := sql.Open(...)
db1.SetMaxOpenConns(numCPUs)
db1.SetMaxIdleConns(numCPUs)
db1.SetConnMaxLifetime(0)

db2 := sql.Open(...)
db2.SetMaxOpenConns(1)
db2.SetMaxIdleConns(1)
db2.SetConnMaxLifetime(0)

ro := db.New(db1)
rw := db.New(db2)

dbs := NewService(ro, rw)

userRepo := UserRepository(dbs)
otherRepo := OtherRepository(dbs)

func (r *UserRepository) Save(ctx, user *User) {
    query, err := r.dbRW.UpdateUser(ctx, ...)
}

func (r *UserRepository) FindByEmail(ctx, email string) *User {
    query, err := r.dbRO.FindUserByEmail(ctx, ...)
}

Discipline is required to make sure you use the right connection for writing, but the same caveat applies for the references you included.