Have you asked your Dr about the timeline and told him/her that you would like to just get on with it?

Your concerns certainly make sense to me, but I'm not a doctor. In the recent past, it was common for them to do "sandwich therapy" where they would do 3 rounds of chemo, then immediately do external beam radiation for a month, then 3 more rounds of chemo. But that was before they started adding Keytruda, which has just been in the last year. (I was being treated exactly a year ago, and one of the three opinions I got, which were all different, was sandwich therapy. Chemo was just carboplatin/paclitaxel. No Keytruda.).