more from Bnet to singleplayer?

is there a way?

I started on Bnet but I realized I beside finishing the campaign in group afterward id rather paly solo on P8, is there a way to transition?

Not legitimately. Have to start over.

Nope gotta start over

It's the XXI century. You can choose whatever you want to be.

Starting over is a spiritual journey

you want to transition?

Use hero editor to manually copy everything .
https://d2runewizard.com/hero-editor

is there a way to not "manually" copy? but just like export/import?

I don't think so, all your online character data is stored on blizzard servers.