I’ve got to stop leaving stuff out for brevity! I was going to mention that too, but I’m trying to not be so verbose in my posts!
I only mentioned the Mossie because of the mention of the Pathfinders, which reminded me of my old comic book; not that they could be used to carry an A-bomb. 
Would Berlin have been the most high value target? What about nuking Essen?
Same thing happens to me - I compose a perfectly cromulent post, and then some know-all jerkwad has to chime in and point out something I didn’t include. 
Indeed, it just occurred to me to check out a Mossie’s maximum payload on my own initiative.
Those were just psychological in purpose anyway. I recall reading (from the writings of Freeman Dyson IIRC) that the British government at the time had been told that removing the turrets would increase survival rates by letting the bomber fly faster, but decided that the psychological benefits of being able to shoot back were more important than actually not dying.
Well, if they target well enough, could they take out Hitler and his entourage? Even if they were in the deep recesses of his bunker?
<nitpick>
It would have been more like half that. Hiroshima was 1.6km, and that was due to the blast being ‘focused’ by the mountains around Hiroshima, which Berlin doesn’t have.
Also most buildings in Hiroshima were wood with tile roofs; Berlin had a lot more stone & concrete buildings, which would have been more likely to withstand the blast. Remember the photos of that domed building in Hiroshima? That was a concrete building, and it survived, despite being only 150 meters from ground zero.
And the “near-complete loss of communications” would likely have made German armies more effective, given the quality of Hitler’s micro-managed military orders.