Distribution Group Owner Licensing

Hello, I am fairly new to Exchange Online although many years working with Exchange On-Premise. I recently came across an issue and wondering if anyone has any advise.

We have a number of Distribution Groups, and in a lot of cases we add an end user as the group owner so that they can maintain the group membership, obviously found that this does not work if using On-Premise groups as we are still in Hybrid mode. However, I have created new M365 Distribution Groups and in some locations it is not possible for the end user to maintain and instead it is the local admin that will do this. This issue we have found is that if they are using the Exchange Admin Center (M365) and are using their admin user, they cannot add their admin user as an owner unless it has an E3 license. As these users don't require E3 licenses for their daily work, I just wanted to know the least cost license for this "role" or do you have a better idea as I am probably still thinking in an On-Premise mind-set.