Privileged MessageContent intent limits after deploying a discord.js bot past 100 servers

I maintain a discord.js v14 bot that uses prefix-based message commands, which means it relies on the privileged GatewayIntentBits.MessageContent intent, declared in the Client options and toggled on in the Developer Portal. It works correctly in my test guilds: the client logs in, messageCreate fires, and message.content is populated.

My concern is what changes as the bot grows past the roughly 100-server threshold, where Discord requires verification and approval for privileged intents. I want to understand the failure behavior before it happens in production rather than diagnosing it from logs afterward.

The documentation describes the approval requirement, but I am unclear on the operational details: whether an unapproved bot that crosses the threshold keeps working with the intent it already has, starts receiving empty message.content silently, or fails at login with a disallowed-intents error. I also want to know whether the startup warning discord.js emits about missing privileged intents reliably distinguishes "not enabled in portal" from "enabled but not approved at this scale", since the log signatures seem similar.

Specifically:

• Does intent approval status change runtime behavior for a bot already connected, or only at the next login/session?
• Which exact log output should I alert on to detect an intent-related regression versus a token or sharding fault?
• Is migrating to slash commands the only way to remove this scaling dependency entirely?