Any Republican that could conceivably win New Jersey would never win the Republican primary.
Someone like Jay Webber could. If he became a congressman and had a national profile being a Freedom Caucus suburban man; he'd do well in Iowa, South Carolina with the evangelicals, New Hampshire with the tax cutters, California and NY and NJ with the suburban Republican type voters.
Webber would coalesce the remaining wings of the Republican Party lane, he'd appeal to the Trumpists with the immigration cred.
I live in NJ-11, the margin by which Webber lost was surprising and not the least because he was successfully painted by Democrats as a right-wing extremist. He has no future in federal politics, and being Freedom Caucus up here is not the way to go. Had Scott Garrett not been tossed in 2016, he very well could have lost by Comstock margins in 2018, he was always out of place which is why he fell before Lance or the others. Morris County is trending D and much of the rest of NJ-11 is the rich suburbs in western Essex County (stretching from Livingston to just west of the Oranges) and Sherrill is from there (she's from Montclair), so you can expect a sizable overperformance there. No one is beating Sherrill this year and Jay Webber won't have any luck in a rematch.
Is Webber gubernatorial material? In 2021 or 2025? New Jersey is a antitax state economically, but very socially liberal.
Sherrill could be vulnerable in 2022, or 2024, she may run for Senate or governor in 2024 and 2025.
It's going to be a while before any Republican is competitive statewide. Christie got lucky because Corzine was historically unpopular and then he rode on the Sandy wave.