Is there a way to switch Mac OS boot partitions without going through System Preferences? I have just viewed a YouTube video on how to set up my Mac as a Mojave/Catalina dual-boot, using two APFS volumes on the internal drive, instead of using a bootable external drive.

But is there a way to select the boot OS without having to go into System Preferences every time I want to switch? And is there a way that's compatible with the bootable APFS volumes being encrypted?

So far, everything I've seen online about Boot Camp seems to indicate that it's strictly for setting up a Mac/WinDoze dual-boot. Am I mistaken? Can it do what I want here?

By comparison, my DOS/Linux dual boot at home boots to a GRUB menu, that allows me to select the desired OS (PC-DOS 2000 or Ubuntu Hardy Heron), defaulting to whatever OS I used last.
You can hold down the ⌥ Option key (also known as Alt) at startup, and that will show you all the available boot volumes.