I posted similar thoughts/questions yesterday, and after not getting any engagement I searched and found your note.

My note is here:

https://primal.net/e/note14u0gmsa0h9lydu5javn6qf2wdrs4cmf59mp2tg0w0yhwpkz5thdq2p42ra

I watched the logs on my bitaxe for a while today and saw all the stratum client and server messages. I couldn’t figure out how to decipher the nbit field, but it’s clear that the local public pool instance is lowering the difficulty like all pools do. Like you, though, I’m very interested in the block template origin.