IMHO the situation is this: Are your actions make Trump feel good? The feeling can be induced by making him richer or boost his ego.

Those "X country will invest in US" stuff are about boosting his ego through good press. No one follows up anything, they use the "flood the zone" strategy, which doesn't allow the public to have long attention span.

Also, it appears that Trump likes numbers around $600B. Everyone is "investing" around $600B, even companies like Apple. When Mark Zuckerberg was asked what Meta invests, he threw the same number and later was caught ona hot mic asking Trump if he liked the number as he admitted that he was not prepared. So yes, just say you are investing $600B in USA thanks to Trump and smile to the cameras. Don't worry about the money, this is for boosting his ego and not about the money. Actually investing is dangerous, if it goes bad(like with factory incident) it creates problems for his campaign, helps his opponents and may hurt his ego, just do the show no need to complicate things.

If you want to do the money thing, you invest in his crypto or donate to his campaign etc.