With the Amos explosion on Falcon 9 IIRC the issue was with burning kerosene seeping into the pad, damaging it quite a bit. Both methane and liquid oxygen should burn or evaporate before really pooling on the pad infrastructure, so there could really be less damage.
Still, there was probably more energy stored in the Starship propelants than in the Falcon 9 case.
I'm not so sure. The biggest explosion I saw in the video was right at the base. I think that the liquid methane spilled and fell to the ground. Probably the oxygen tank also burst by that time, spilling LOX right into the path of the falling liquid methane - creating a nice mixture of methane and oxygen right at the base, ready to explode.
(It'll still be fucked, I just wouldn't expect a crater?)