Other than hype there is no showing from either of the characters mentioned in your post that would make any sane human being think "she would do things there is no coming back from" or "dd would not come back from" or "galactus would erase him".
I agree DD would lose against those cats, but the way you make it sound is ridiculous.
Ignoring Pheonix's telepathic abilities, which arguably may or may not work on Doomsday, her telekinetics would destroy him. Everything from crushing his heart inside his chest to destroying his brain would put him down. My thought would be she'd tear him apart then burn and scatter the pieces, which I'd be impressed to see him return from.
DD is purely solid. He has no organs. Plus you just proved to us that you don't know anything about DD when you rendered the silly comment about her tearing him apart. DD is one of the most durable beings in comics (even without instant regeneration and evolving on the spot). The Omega Effect couldn't even tear him apart. Also DD is faster than her. He would tear her to pieces before a thought can flash through her brain.
Originally posted by h1a8
DD is purely solid. He has no organs. Plus you just proved to us that you don't know anything about DD when you rendered the silly comment about her tearing him apart. DD is one of the most durable beings in comics (even without instant regeneration and evolving on the spot). The Omega Effect couldn't even tear him apart. Also DD is faster than her. He would tear her to pieces before a thought can flash through her brain.
This^