Auto-payouts usually follow the selected source account — verify and test
Translation: "Now a different question for experts. If I currently have n amount of BTC in my main account and I set up an auto payout to an external exchange, will the auto payout send only coins that are on the mining account? Or will the ones in the main account be transferred as well?"
My view: Auto-payouts typically apply to the specific account or balance type you choose. If the payout is configured for the mining/rewards account, only funds in that mining account are usually scheduled for automatic withdrawal; funds in your main/trading account normally remain unless you explicitly select that account as the source.
Because implementations differ across exchanges, you should confirm the source account in the payout configuration, check thresholds and whitelists, and if in doubt run a small test or contact support.
Analysis
Recommendation
Check the auto-withdrawal source account in settings, confirm thresholds and destination whitelist, perform a small test withdrawal, and contact exchange support if anything is unclear.
Disclaimer
The Analysis and recommendations provided are for informational purposes only. Any investment decisions should be made at your own risk. Past performance is not indicative of future results. Always conduct your own research and consider consulting with a financial advisor before making any investment decisions.