Must admit I'm not that familiar with Bellingcat - But I call BS on your theory, what they ousted about the 2 "possible" GRU agents that went to Salisbury, even the BBC has gotten involved and found associated evidence: https://www.bbc.co.uk/news/world-europe-45694123
I understand there is a movement in the UK and abroad that doesn't believe the mainstream story surrounding this. Ironically my next door neighbor is one of them, in his word "Do you really think the russians would come here to do that? when they could have just assassinated him when he was in russia, or made it look like an accident with a hit and run".
Usually, I'm the first person to call BS on politicians, but in all honesty, I believe this. The Russians have had a lot of success, where the West turned a blind eye, because it was too focused on "terrorism" and distracted by the US's new Boogeyman (China) - So I can easily see the GRU has started to see it self as untouchable - By going public with type of information, it removes the GRU's anonymity and their ability to operate (eventually, then'll run out of agents!)