Smartest way of transitioning into ETF ownership from single stocks

Hi! I have about $3mm worth of stocks. I'm sitting on about 100% returns, so 1.5mm in long term capital gains.

I invested 1.5mm 5 years ago, and now its worth 3mm.

The stocks I picked have pretty much mirrored the S&P500. It slightly beat it by a couple of basis points. I'm thinking I should just move it all into ETFs.

Is there any smart or tax advantageous way to do this?

Or is this just a bite the bullet kind of thing where I sell everything, pay the tax, and then buy the ETFs?