Want To All Post In Block Editor BY Default (Ultimate CVS Importer Plugin)

HI,

Whenever i am uploading multiple post via ultimate csv importer plugin.

initial few H1,H2 and paragraph are in different font and headings ,
snapshot : https://www.awesomescreenshot.com/image/21039394?key=e2e7611cd2e2633232a7622712a79e27

Then i need to edit the post and need to click on this "Classic" option (https://www.awesomescreenshot.com/image/21039437?key=7dfadd2d4767deee2214284c8a35b095 ) and then need to convert blog into "Convert Block" (https://www.awesomescreenshot.com/image/21039531?key=f003506c662701b4397aecf5a87217c3 ) to make blog proper.

i can't do it for all blog, as i am having big list of blog , i want solution for that.

i want all post in block editor by default whenever i am upload via ultimate csv uploader

Thanks