Learn how to create a Shortcut on your iPhone that you can activate with your voice to turn on Do Not Disturb. The Shortcut will then ask you for a number of miniutes and automatically turn off. You can also set it to activate silently as a Home screen icon.
If you want something faster than an external hard drive, and better than a USB Flash drive, you can build an external SSD drive with an SSD and an enclosure. I built a 256GB USB 3.1 external SSD for less than $70 that works great on my Mac. Learn how to build your own.