I'm not the best to tell you this because of my history with shinys XDDDDDDDDD.
Even if you do 30,000 meetings, that is not a fixed number, it is mere speculation or, so to speak, a non-fixed probability.
You can make eggs now and easily have around 90,000 encounters and even less, breed alpha capes and luckily you become shiny.
I wish you good luck in your search and may your drought end soon, no matter what happens, never give up, you end up giving up and lose all the effort you accumulate gl