It's important to understand the difference between GMAT optional and GMAT waiver to get a clear picture of what your waiver application should include.
GMAT Optional
Some schools have simply made a short term decision to remove the GMAT from the list of required elements of an application for their MBA programs. Most are pointing to an un-level playing field due to some applicants being forced to take the Online version in sub optimal conditions with considerable distraction and technical failure risks. Either way, the program is saying that they will find other ways to get the same performance metrics as the GMAT normally provides.
GMAT Waiver
Very different from above. More case by case and focused an explicit process that forces that applicant to make a balanced argument for the waiver. They want to you to demonstrate an understanding of your job as applicant -- to provide reasonable objective ways to assess you quant and verbal abilities to the point that they will not be obstacles to your success in the program.
The GMAT included application is still considered the default -- you are asking for an exception waiver. The answer should be balanced between reasons for not taking the GMAT (Covid, life situation etc) and providing alternatives to the assurances on core skills the GMAT provides.