German media saying 40m, Sport saying 25-30m.
With Sport's lousy reputation I'd say German media are closer to Bayern's valuation.
In fact, with Sport's lousy reputation there's a high chance of this just being random BS to sell more papers. It's silly season, people with their vacations, tourists arriving, gotta sell them papers and clicks.
I'm also not sure Dortmund really are insistent on 80-90m either. Seems like a tactic to sign someone else and justify that by saying all other options were impossible.
Bartomeu afterall said Barca are set to dominate further by signing Arda like he was some once in a lifetime player.