With this kind of margin, Comstock would definitely lose, maybe even Janett Ditmar could win.
It's really hard for me to see Comstock losing without similar Republican freshmen like Katko and McSally (and Rubio, in the Senate), who've successfully distanced themselves from Trump without alienating his supporters also losing, and there's been no sign of that happening.
OTOH, I could definitely imagine Dittmar snagging an open seat, or coming uncomfortably close, with numbers like this atop the ticket.
Comstock's fear has to be that enough Republicans don't show up to vote.