How do I make sure I can take full advantage of the current or upcoming EV tax credit? Is it as simple as updating 4(b) on my W4 to allow for an extra $7500 deduction?

I plan on buying a new electric car next year. Although we do not have a guarantee on the new proposed bill of updated tax credits, I will still focus on grabbing the existing $7500 for an eligible vehicle. I never owe taxes and always get a refund. Can I just update my W4 to have a large deduction to make sure I get to use my full tax credit?