How to disable show picker?

How many times ever I unclick show open core boot picker > Then click on build and install open core > selecting the disk. After that when I restart, it is again booting back to Mojave, which is my other partition By default, if I have to move to Sonoma, I have to press hold option key, then go to EFI partition and select Sonoma within five seconds else it blew back to Monday. What can I do now?

submitted by /u/Infamous_Pride8095
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