If you win a lump sum, studies show that the best time to put it in the market is all of it right now, not trying to time the market or DCAing it into the market. Of course, you could get unlucky, so that you're initially in the 2000->2013 style window, but you can't know that at the time.
Of course, most of us do / should invest smaller amounts over time, just because that is what our earning profile is like.
2000+ was only an issue for US-only, equity-only investors: if you were globally diversified you were fine. Even if you were US-only, but had at least 20% bonds, you were also fine:
* https://www.forbes.com/sites/investor/2010/12/17/the-lost-de...
Which is the whole point of DCA. It makes it less likely to get unlucky. (It also makes it less likely to get lucky. DCA makes it more likely that you will simply regress to the mean.)
* https://ofdollarsanddata.com/the-cost-of-waiting/
Author has a repo where he often shares the data/code used in generating analysis:
https://m.youtube.com/watch?v=X1qzuPRvsM0
TLDW: just invest it all, right now, in value small caps.