High database load and deadlocks in loadtesting environment for 4.66.0 RC

[jmwatts]

Fleet version: v4.66.0 Web browser and operating system: n/a

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💥  Actual behavior

🧑‍💻  Steps to reproduce

1. Spin up load test environment with 30 fleet containers, 200 loadtest containers
2. Review performance insights for writer instance

🕯️ More info (optional)

Internal Slack thread