TM edit post one by one which is I guess for replacement word. like if one post has 10 replacement work it should work like this way.

but let say we replace post from text file, shouldn't it fine to use multi-post edit? and someone unknown reason Wordpress edit is slower than normal MyBB, xenforo site. coz of platform?

Sites don't allow to edit multiple posts at the same time. They just show error of mismatched tokens or flood warning.

For editing speed it's really depends on the server. Probably the server on which the Wordpress is running is slower (it will load slower via browser as well).

it's same server. i checked mybb, phpbb, xenforo is super fast like 1K post edit down within 10~15min or less I think. for Wordpress I will take more than a hour.

Might be that Wordpress script is a bit slower since they have more going on, more database requests and other things.

It would be the same via browser.