Retirement tax questions

Kudos DanaB27 and fanfare, and Intuit/TTax as well for hosting this community forum. Wonder if ChatGPT or other AI-bots are as yet as knowledgeable on the tax code. As for fanfare's final post about  gaming the IRA machinery to juice up one's Roth IRA balance by making an excess contribution, use this new balance to strategically invest in a way that produces a windfall, then removing the original excess amount, paying tax on the windfall gain, and ending up with the gain left in the Roth IRA to grow tax free! Have I understood this correctly?  Lastly, regarding IRS crosschecks, it's always been my understanding that things the IRS can easily check using automation (like numbers from W-2s. 1099s, and Form 5498s) will always get caught.  In past returns where I overlooked one of my 1099's it's my recollection that the IRS eventually detects this and notified me in a CP2000 letter.  Thanks again you all!