When you schedule data deletion in GA4 (via Admin > Data Collection and modification > Data deletion requests), Google give the following three warnings:

However,
There is no official Google documentation confirming that GA4 will process multiple data deletion requests in the exact order they are submitted, or that one request will fully complete before the next begins if both are scheduled close together.
Google does document that there can be up to 12 active (grace/pending/in progress) requests per property at any time, which implies overlapping processing is possible.
The best practice is to wait for the first request (such as parameter deletion) to be fully processed before submitting the second request (such as event name deletion).
For example,
To fully remove an unwanted event and its parameters from GA4, two separate data deletion requests are needed:
>> Delete all parameters for the specific event (“Delete all registered parameters on selected events”).
>> Delete the event itself via the event_name parameter
Each request enters a 7-day grace/preview period before deletion begins.
After this period, actual deletion can take 7–63 days, depending on data volume.

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