Wrong.

The 3x etfs reset the leverage daily.

As a result, longer-term gains can be greater than 3x and longer-term losses can be less than 3x.

However, whipsaws are worse.

If the market goes down 1% then up 1%, then $100 turns into $99.99 but $100 in the 3x ETF would turn into $99.91. Whereas if you just had 3x margin (say by a HELOC on your house) so that instead of putting in $100 that was 3X ETF, you put in $300 into a 1X ETF, the $300 would be at $299.97, which divided by 3 is $99.99. With non-resetting leverage, you only lose 3 cents while with the resetting leverage, you lose 9 cents. With no leverage you only lost 1 cent. The losses due to whipsaws are called volatility decay, and the daily resetting leverage is hurt the worst by it.

But repeated moves in the same direction are better with daily resetting leverage. 1% up twice in a row is $102.01, so 2.01% for no leverage, $106.09 so 6.09% for daily resetting 3X ETF, which is more than 3X the nonleveraged (2.01*3 = 6.01). Works the same way for losses in that the daily resetting of the leverage makes you lose less than if you had non-resetting leverage.