These days a Nasdaq ETF is likely the best bet (it's what I use in my IRA) since it has been conistently outperforming the S&P 500.
I'd be cautious with the more exotic leveraged ETF. Instead, for my non-investment accounts I've been mostly holding the Mag 7 since last year (after rotating out of pandemic stocks following the rebound). I shared my results over the last couple of years on by blog where I document my thinking for future reference/improvement (https://gmays.com/2-year-follow-up-on-buying-the-dip-on-pand...). My current IRR from that portfolio is 83.70% over the last couple years for context.
QQQ has done great the last decade, but that's no guarantee it will outperform the next decade. Make sure you understand what you are getting yourself into by overweighting in the tech sector, and that it's a plan you can stick with during the hard times.
I'd be cautious with the more exotic leveraged ETF. Instead, for my non-investment accounts I've been mostly holding the Mag 7 since last year (after rotating out of pandemic stocks following the rebound). I shared my results over the last couple of years on by blog where I document my thinking for future reference/improvement (https://gmays.com/2-year-follow-up-on-buying-the-dip-on-pand...). My current IRR from that portfolio is 83.70% over the last couple years for context.