With a spare megabyte of RAM you could also install Workbench or equivalent in a resident bootable RAM disk ("RAD:"), so you could boot from RAM with no moving parts.
Of course that will only work for a warm boot/warm start, not the first "cold" boot.
Some details here: https://www.amigareport.com/ar139/p1-6.html
In general, booting an Amiga from an HDD is quite fast, and can certainly be far less than 30 seconds even when a significant number of drivers and small applications are loaded via commands in S:Startup-Sequence.
It should normally take only ~5 seconds to initialize the hardware and see the display of the CLI window (see below about cold vs. warm boot times)...