A couple of FP1 sessions in F1 coupled with a top-10 finish in the IndyCar championship should see him reach 40-points.
This is where money can come in. And I think Liberty will encourage this. GM-Cadillac pays one or more teams to buy seat time for Herta in a few FP1 sessions and voila. Liberty profits from this as they will get a marketable US driver into F1.
EDIT: And as I mentioned in the 2024 thread, the guy who is overseeing the GM-Cadillac entry is also the CEO of Colton Herta's primary sponsor (Gainbridge) and he personally likes Herta. He will make sure Herta is in F1, one way or the other.