Consequently, it’s a terrible idea.

If anything bigger buisnesses have more ressources to avoid taxes. - Thus having everyone pay the same would lead to large companies paying more than they do now and small companies would be barely affected.

You will have to go after financialization tricks, where healthy companies get loaded with debt, weird tricks with assets and all the stuff the finance industry comes up with that has nothing to do with core function of the company. Now imagine the powerful lobby you have to work against.

Food for thought: in a distribution chain you will find lots of small value adds. Take sea ports, there are loads of companies that handle import of materials or products. The price they charge for their goods/services are dominated by their import costs.

corporations aren't people, and I think you know this. "corporate personhood" means that a corporation has some (not all) of the rights held by individual people. it certainly does not mean that it makes sense to tax corporations as if they were humans that filed a W-2 each year.

what do you think would be solved by jacking up the corporate tax rate specifically? or put differently, whose pocket do you imagine this money comes out of?

the owners are already taxed on any income or capital gains they derive from ownership, employee pay is taxed on both sides, and retail customers pay sales tax. none of those taxes are necessarily optimal, but their impact is at least better understood than corporate tax.