Given the same amount of time we'd have improved on our first atom bombs and made them much more lethal, or damaging, or whatever.
Time marches on and science progresses.
Hiroshima had 1000 times more raw energy, plus, lots of it was penetrating radiation and thermal, not just blast. And even given that, got ~30% lethality within 3 miles.
I’m familiar with FAB and therbobaric physics. Even an enhanced thermobaric with a CL-20 core and ethylene oxide load won’t match that, at 11 tons TNT eq.
The Russian bomb is only a little bigger than our MOAB.
Sorry, they are making the lethality numbers up. Makes sense; you want your enemies to be frightened of your capabilities.
Just kids Havin fun