The Saudis definitelyfinanced a percentage of Elons purchase and likely the Russians and Chinese as well. That is public record. How does that factor in?
I don't think financing is a problem. The issue is proving that they paid him to influence elections, gave them secret information he had from his government contracts, etc. If foreign investment alone was enough most every company in the U.S. would be guilty of espionage/treason. In a global economy, you are going to have some level of foreign investment. Unless, of course, you choose the course of isolationism which I doubt you would.