Oh I’m sure it’ll be fine and you’ll forget this happened by spring . No need to worry ! Roses are very tough

It will be fine. It may put out some new growth this fall because of the pruning, and that will most likely die back over winter, but it will rebound come spring. They are very forgiving.

Thank you, and on the subject of this same rose.. should the laterals-as-thick-as-canes be cut off entirely rather than cut back to 8” stubs? Can stems that thick bloom? If removed will new stems (proper laterals) take their place?

All can bloom. Leave more, have more blooms.