So why on earth would Trump lift a finger to help Heritage pursue their policy preferences?

It wouldn't be to help Heritage pursue their policy preferences. It would be to help Trump pursue his own preferences.

Let's say Trump would like to enshrine his Schedule F executive order into law rather than just an EO. That is something I'm fairly sure he would like. Perhaps he needs a few more Republicans to back it, and they are holding out for a nationwide abortion ban. So he'll let them add the abortion ban to the bill to get their votes for Schedule F.

The Heritage foundation has given Trump a list of potential bargaining chips to use to get votes he might need in Congress.

Of course, don't get too worked up over my choice of issues to pair up. It's just an example. It could be any issue that Trump wants paired up with any issue he doesn't care much about but that other Republicans might care deeply.

The point is that there are a good number of Republicans who would back the various bits of Project 2025 that Trump is ambivalent about. And that could easily lead to a fair amount of Project 2025 coming to pass, even though Trump isn't advocating for it.

And that all comes back to Trump caring only about Trump. The parts of Project 2025 that aren't good for him now could easily become useful for him in the future - not necessarily because those are things he wants, but they can become the currency to buy votes or do favors in exchange for something else that he does want.

--Peter

PS. I'm going to continue pointing out that the worst parts of Project 2025 are also the ones Trump wants for himself. These are the parts that would put a severe strain on Democracy itself.