How to increase boot timeout

Hello, I recently installed Kali Linux on my computer, I now have 4 Operating Systems. I want to increase the boot timeout in the grub menu. Right now it's 5 seconds, and I want to make it 10. I tried to do this with Grub Customizer on Ubuntu, but it doesn't change. The first OS that appears in the grub menu is Kali, followed by Ubuntu, Windows 10 and Fedora. When I move Ubuntu to the top of the list in BIOS, Kali no longer appears in the grub menu. I want to have Ubuntu as the first entry in boot, but when I set it as 1st, Kali no longer shows in grub. And I also want to have 10 seconds timeout before I choose an OS.
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