Subject: Re: Harris and the Dem tax proposals,
Together, the proposals would increase the top marginal rate on long-term capital gains and qualified dividends to 44.6 percent.

This is incorrect, and you never linked to your source. The higher rate would only apply to people with over $1 million in income, and the top marginal rate would be 39.6%, not 44.6%. Here's the actual statement:

"It also proposes taxing capital gains at the same rate as wage income for those with more than $1 million in income..."

https://www.whitehouse.gov/omb...

In its entirety, the budget proposal would cut the budget deficit by $3 trillion over 10 years. Any changes to the tax law would require approval of Congress, though.