So GTech is out of the question now.
Note that with AP credits, it may be possible to graduate in 3 years (thus saving some money). If you aren’t interested in anything besides physics and math (and taking the bare minimum gen ed requirements), that is something to keep in mind.
So, if you really don’t want Stony Brook, your options are
–3 years at Cambridge at roughly $145K total.
-3/4 years at CMU for $120K-$160K.
–French prepa
–gap year (or prepa and bail after a year) and apply to schools where you may get giant merit scholarships. Looking down the list of top-ranked physics unis in the world by ARWU ranking, JHU offers a tiny number of big scholarships. UChicago use to as well, but they have become almost impossible to get as the U of C has climbed the rankings. If you’ve already been rejected from those places, don’t bother, however. Actually, big money from both is almost impossible. More likely are UArizona (essentially guaranteed in-state costs if you are a National Merit Scholar, which I assume you are) or possible Banneker-Key (full-tuition) at UMaryland. Those are giant state schools with rather uneven talent in the student body (especially UArizona, where a ton of your classmates will party and then drop out). But they would have some well-respected physics faculty. And honors college may make it worthwhile.
–Take whatever classes you need at a CC/Stony Brook and transfer for the final 2 years somewhere for physics full-time (that would cut down costs to 2 years). The publics are more open to transfers (looking down the ARWU list again, I see Berkeley, UCSB, Colorado, UMich, UCLA besides UMD and 'Zona). Cornell also takes in transfers, but mostly the contract colleges from SUNYs and NYS CC’s that they have articulation agreements with (so not physics).
–Some combination of the above: Prepa and then if you don’t get in to the French school of your choice, see if you count as a transfer or freshman admit and apply again to various American schools listed above. Columbia SGS is easier to get in to and many take a lot of credits there with them, but they require a gap of 1 year in schooling.
If you don’t go the French route, a funded 6Y American PhD program (where you pick up a Masters along the way) straight out of undergrad is the way to go (it would be silly to pay for a European Masters). I think most American unis would be fine with a 3Y Cambridge bachelors (some may be insistent on a +1Y Masters, but you can probably safely ignore those).
I have no experience with the French system, but it sounds terrible, so your only good choices may be paying up for Cambridge (if you decide on that over CMU) or taking a gap year and trying for big scholarships (or Stony Brook).
Hmm. The Arizona NMF scholarship may be out of the question. Seems like you would have had to have listed them first already. They do allow you to stack scholarships, but that option may be out now.