Her is the community gathered data on the amount of battles required to reach the first 5 Kingdom Crowns and the 2nd lot of 5 Kingdom Crowns.
I must say a HUGE thank you to the team of data demons who kindly submit their info each day: @ALP @Dorgath, Shirley & Guildmate, @Ashasekayi, Heff and Kei
I omitted the data from trying to find crown 10 during the vault weekend as it was skewing the results, but generally most gave up after 150 battles.
If you want to inspect the data or get involved, please find the relevant links in my post 4 replies above.