LH just updated their winter intercontinental schedule and equipment assignments on Monday. It is possible (probable?) that there may be additional changes to the winter schedule, most likely sometime in August. This may or may not affect your route. The North Winter 2024 (NW24) schedule runs through, I believe, March 30, 2024.

As of right now, the 748 is scheduled for NW24 on EWR-FRA, IAD-FRA, MIA-FRA, LAX-FRA, SFO-FRA. (JFK-FRA is the 744 for NW24). As with the above, these equipment assignments may still change! It's possible the 748 is on other US cities, I haven't checked all of them.

Note that if your return flight is on/after March 30, 2024, that will be part of the Summer schedule which will not be firmed up for many months still.

I would not make any changes to your reservation yet since I do expect there may be some more updates to the NW24 schedule still Last year there was a big update in July and a then another big update in August, following by minor tweaks only after that. By September, you should be relatively safe, though things can always change at any time.