Hi Alex,
After deleting Standard_E16-4ds_v4 VM you should see your quota usage go down. For example, if you navigate to My quotas you should see usage for Standard EDSv4 Family vCPUs for the region go down by 16 from the level it was at when the VM still existed. The quota limit itself should stay the same.
Above assumes the VM was not a Spot VM.
Are you seeing something different than what I described?
Please click Accept Answer and upvote if the above was helpful.
Thanks.
-TP