I mean, 2 mil is 40k a year for 50 years. 30k per year for 75 years. I've no idea how old you are but I doubt I've got 75 years left. There's a million nice places in the world you could live for 30k per year. 30k per year is above the average annual income for Portugal and Greece for instance. 40k per year is above the average annual income for Japan, Spain, Italy.

You could literally do nothing, stick it in your current account, live a slightly above average life in a nice place for the rest of your life, never working, never worrying, never following investments.

You would, of course, also invest. But you need so little return, and can put it in such long term, that literally anything low risk will suffice.

So my real answer to your question is to set your living standards and place of residence to a level where literally anything would see 2 mil lasting a lifetime, rather than living luxuriously. Because I value not working ever again more than a boost to lifestyle. You can bet I'd find a budget for a few toys. Buy a Day-sailor. Paint. Touring Bike. Camper Van. Set up a Soup-Kitchen. There's tonnes of budget to do whatever you want.