@AllisonHowell Thank you, this is how I hoped it would work; however the test did not.
My Sandbox course is set to Term participation for FY23 (July 1, 2022 through June 30, 2023.)
The student was invited (and accepted) today - November 2, 2022.
All due dates on the student's view are calculated from the July 1 date. The gradebook from my view shows all assignments as missing (red).
ETA - I believe I found the problem. This "student" had been enrolled before. (It's a student account I set up with my personal email.) I had removed the student from the course, then added them back. Even though these were new assignments created today, and the student had not submitted any work prior, it must have retained the original start date. This could potentially be a problem with our secondary students who are added and removed from courses regularly.
ETA Part 2 - I added another student who had been in this course but removed a long time ago, and it seems to be working fine. I tested changing sections (with different course pacing) and it adjusted due dates even though a submission had been made. Important to note that due date updates on the student view are not immediate.