Something to consider - latest research is saying a functioning lymph system can be effective in fighting cancer. Will the level of suggested radiation shut down the functioning of those nodes? Or probably a better question, can they tell you the risk that it will damage the nodes so they don’t function (what is their research telling them?)

The numbers the doctors usually share with us are what is the risk of cancer recurrence, or risk of lymphedema (you have those numbers). What I’d hope they could tell you is - what is the risk of cancer recurrence or metastasis when radiation to the lymph nodes has damaged functioning VS what is the risk of cancer recurrence or metastasis when lymph nodes are still functioning after radiation.
I would hope they would have that information. If not, it’s time they go figure it out. With AI support they are able to sift through thousands of details captured in research and parse out this type of critical data.
Then it’s a decision about which facility and where has the best outcomes for not damaging lymph nodes to the point of loss of function if you decide that radiation is part of the answer.

With five of six lymph nodes clear, I would also suggest weighing the type of cancer cells you have/had as part of your decision about radiation. My DCIS had cribriform, papilloma, and solid cell formation. It was the solid formation that I was afraid of. The histology of the cancer says a lot about the aggressiveness of those cells.