I’m sorry to hear of your struggles with the system - I was diagnosed in NL so have had a very small taste of it!
There is a decent argument that PET isn’t very useful for at least 2-3 months after radiotherapy, as there will be a large amount of inflammation and scarring to contend with. CT can still be hard to read (eg ‘dead’ lesions may still show as image artefacts - possibly forever), but would be the usual approach and a skilled radiologist should be able to draw some preliminary conclusions and monitor ongoing interval changes. A ‘blurry’ CT sounds more like bad radiography than anything else to me… however I’m guessing they weren’t rushing to offer to repeat the imaging?
Overall my rad onc said interpreting response to radiotherapy - particularly to non-visceral targets like lymph nodes - can be a bit of an art form which often plays out over multiple scans in the 6+ months post-treatment. My nodes haven’t really shown much pathology on scans since surgery and SABR radiotherapy, though I suspect no-one quite believes they’re entirely disease-free.
Good luck as always.