Borderlands 3 character change?

I have a question…

I started playing BL3 on the PS4 last WE and decided at first to play with the siren, as I also played with her in the two predecessors.

But I'm not 100% satisfied with my choice and I would like to change to Fl4k, but I do not want to start all over again.

I've already tried to create a second user on the PS4 and then let the Spl4k climb a few ranks via split screen. So far so good I thought and have now tried to transfer the "score" of user B (the one with Fl4k) to user A (starting with the siren). Unfortunately, this did not really work then also read on the Internet that probably does not work with the data transfer to other users.

Now to the actual question…

Can I just start a new game with Fl4k (with user A (Main Acc)) and play until the 1st correct save point, then save and quit game and then with the character (Fl4k) on the memory of the siren (just on character change click) continue playing?

As far as I know, this is not possible. The story and level progress is saved separately per character. You have to play the story yourself with the new character. If you want to level it up faster you could at most join another player or friend whose character is already higher. He can then pull you up, as you have already tried in Splitscreen. But even then you have to start the story with the new character over again.

Okay so that means I start with Fl4k again from the beginning.