I have cut and pasted the chart below. It was posted on X by Ernie Tedeschi, former head of the White House Council of Economic Advisors.
Anyway, this chart maps inflation-adjusted median net wealth (assets - liabilities) versus age for Gen Z, Millennials, Boomers etc. And by this metric, Gen Z and Millennials are doing better than Boomers.
Your data uses different metrics - percentage of total wealth owned by people under a certain age, wealth as a percentage of disposable income etc. Arguably these metrics are better at gauging how a generation is doing financially. I think it is accurate to say that Gen Z own less of the total pie than Boomers did at the same age, but today's pie is much bigger in real terms.