one does not simply ICBM into Mordor.

Also. we can easily create temperatures far exiding mount Doom’s lava.

Maybe even ye olde thermite could do something
since the ring posesses magical powers, maybe you can trigger it to release a “magical explosion” some how. but MAGIC is very nebelous in lotr, very little spellcasting, or magical attacks, or effects magic.
I think it’s not about the temperature of mount doom, but the magical effects of the ring being forged there. But I could be way off…
it’s more about a plot device, so any attempt at destroying it anywhere else is bound to fail. alternative, launch it into space like the Voyager,
Do you want space nazis? Cause that’s how you get space nazis.