Hi Tom,
I have noticed your query, but simply have no idea what to reply.
For example, and by best will, I can't provide something like a 'list' of sources one might want or not want to check. I do not have such a list.
What I'm doing is to read releases by the Ukrainian GenStab, and the Russian GenStab, and then cross-check these with reports from a myriad of sources, including hundreds of direct contacts and appearances in the social media. That's hundreds of different instances, each of which might be right one day, and not at all the next one (indeed: right in one minute, and wrong in the next).
It takes a lots of 'not-really-academic' approach to 'distillate useful information' from all of that: that's where the decades of experience in monitoring warfare is paying off.
....and even then: be sure, when I look back at some of my reports from 'early during the war', I wouldn't write them them way I did: I simply know much more nowadays, and would explain diverse developments in a different fashion.
....really, no idea where to start, except, perhaps recommend you the following: run a similar process: i.e. compare what, for example, the Ukrainian GenStab has reported on what day, with what was really going on (which is getting even easier the more time is passing by and more additional reports are becoming available).