Even the greatest yogis get ensnared by the bear-traps left lying around by Nagarjuna. I'm way under qualified for this stuff, eg: Jigme Lingpa was rangtongpa when discussing from sutrayana level. Dudjom Rinpoche was a shentongpa. But both talk Dzogchen when talking Dzogchen.
Once you use the term 'doctrine', you've already shifted the conversation to a tangled, looping web of context-dependant doctrines. You can't say 'doctrine' and then talk about your interpretation of what the doctrine is. It's a magic word. A shitty magic word at that.