Here's a way to re-enable the startup sound on the 2018 Mini.
Thanks and a tip o' the hat to forum member alfogator for this post in the MacBook Pro forum:
forums.macrumors.com
I tried it on my 2018 Mini, and it works there, too...!
Thanks and a tip o' the hat to forum member alfogator for this post in the MacBook Pro forum:
Startup chime
https://eclecticlight.co/2020/02/22/how-to-enable-the-startup-chime-on-recent-macs/ 😁
I tried it on my 2018 Mini, and it works there, too...!