I can only address part of your original questions.
At age 69, I had the 5-blast RT, on an MR Linac machine- the latter point is significant, as the machine is ( purportedly) more precise in its targeting, so there is less risk of unintended peripheral damage. Given the higher dosage rate, that seems (to me) to be a worthwhile benefit.
In the event, I had an easy run of it- no radiation burn, no tiredness, no urinary issues; in fact no significant side effects other than bowel looseness for a ( very) few days.
It is still a relatively unusual treatment path, (although my onco guy thought it was the future) so there is no large base of statistical data to help you, I'm afraid.
As for the 'treat or wait' part of your question: it's 30% data driven and 70% emotion driven......
Good luck with whatever you decide.