The Approvals app is great for simple scenarios like purchase approvals and event attendance approvals.
There is a problem with more complex approvals. Say you need approvals from 2 out of 5 designated people, then validation stops this from being done.
The current validation does not allow the same person to be in multiple approver groups. This validation should be removed.
There are other solutions that allow this such as www.KissFlow.com and www.integrify.com
Suggestion:
The Microsoft Teams Approvals App should allow the same individual user to appear in multiple approver groups.
This modification would give the flexibility to allow more complex approval scenarios.