Fact: Revenue from the income tax goes into the General Fund, for lawmakers to spend any way they want to

Just 5% is required to go to education.

From the House Bill report for ESSB 6346:

Distribution of Revenues. The new tax revenue will be deposited in the State General Fund to fund the tax relief in the act, including the new sales and use tax exemptions, the expiration of sales taxes on certain services enacted in 2025, the expansion of a small business tax credit, and the WFTC program, including its expansion. Each fiscal year, beginning July 1, 2029, 5 percent of the revenues will be transferred from the State General Fund to the Fair Start for Kids Account.