"Exceeded maximum execution time" when concurrent Google Calendar Trigger are running - google-apps-script

Question

I have a Google Calendar Trigger which fires whenever a change in ones users calendar is detected. The Trigger sends some data to a 3rd party system and does some logic. It is important that concurrent Triggers are not sending at the same time.
Therefore I am using the Lock Service which prevents exactly this.
var lock = LockService.getScriptLock();
try {
lock.waitLock(30000); // wait 30 seconds for others' use of the code section and lock to stop and then proceed
} catch (e) {
Logger.log('Could not obtain lock after 30 seconds.');
}
// this can take a few seconds
doSomeStuff();
lock.releaseLock();
// END - end lock here
return;
The problem is that sometimes the execution of a Trigger can take up to 10 seconds and it also can happen that sometimes multiple trigger are executed where every Trigger holds the lock.
This means that that the total execution time can easily be exceeded.
In my opinion this can not be solved with Google AppScript only. In order to handle this I guess the best way would be to have some kind of a queue where the trigger writes to and then Google Cloud Functions takes the data from this queue and runs the logic.
How to solve this?
The only queue like resource I could find in the Google World was Cloud Tasks but I am not sure if this is the best fit (it also needs a lot of setup work) when there are 10K Users where everyone has a calendarTrigger running.
Another Idea was that every UserTrigger writes the data to a database like Firestore and in the backend Google Cloud Functions read and delete the data to run the logic. So in this case the db would work also as a simplified queue.
In both cases the actually logic doSomeStuff() has to run in Google Cloud Functions. However since there are 10K users where every user can fire multiple Triggers I want to have full control over the amount of Google Cloud Functions run at the same time.
Summary
So in my head the solution is something like this:
trigger writes to
-> Queue (DB? Cloud Tasks?)
-> Backend Function watches Queue (Cloud Functions? Compute Engine?)
-> starts (max amount) Cloud functions to dequeue and run actual logic
Questions:
is such a "complex" structure involving those resources necessary?
if so, what are the best Google Cloud Resources to achieve this?