if lowering taxes does not bring companies back, what will?

I think this is the wrong question to be asking. If companies want to leave the country, I think we should wish them luck and observe that they won't be bringing any of their land or factories with them. And if they didn't have any of those here, and were outsourcing these jobs overseas, then they weren't really producing anything of value in our country anyway, and their role as middlemen is quite replaceable.

Instead of thinking about "how are we gonna entice companies here?" just focus on domestic consumer demand. someone is gonna show up to try and satisfy that demand for money.

Consider that the McDonald's company has had to adjust its operations quite comprehensively in order to make its various operations around the world compliant with e.g. local labour laws. In some cases, complying with those laws has proved expensive and has meant McDonald's had to live with slimmer profit margins, a higher consumer price point, or both. But as far as I know, there is not a single one of those markets on Earth where McD's has had to shut down operations entirely.

When you make it a little harder and more expensive to do business in your country, most entrepreneurs will still decide that some profits are better than none at all.