I think you would have to have a time-based trigger run at the start of every potential meeting slot to check your calendar and set the DND status accordingly. Calendar events are not an available trigger. So not impossible, but even re-using the same shortcut, the set-up initial set-up would still be quite tedious.
I remember using a “$” in my meeting titles along with Tasker back when I used Android that did exactly the same thing.
Note that no third-party apps give you any automation triggers, only actions. Apple’s sandboxing and security approach preclude this.
If you are okay with a more manual trigger, you could use one of the back tap accessibility options or an NFC tag to trigger your DND - or even just tell Siri. There are options to run the automation, just not so much around triggering the automation without user initiation.
Q) What’s the reason for the concern about location accuracy for triggers?