For someone looking for “diversification”; I’d avoid individual stocks (3M in this case). S & P 500 ETF is a good choice (IVV, SPY, VOO, etc). When you talk about “generating cash flow”; are you talking about dividends? If you are; Total Returns is more important. Last point; I’m assuming you’ve looked into the tax implications?
If you’re using IBKR, they should be familiar with the tax ramifications for international investors.