Do not try and update any of the system apps via Aurora Store!
As far as your issue: microG uses the same package name as the Google Play Services core. What your seeing in Aurora Store is the Google stuff, not microG. Don’t forget, Aurora Store is just a front-end to the Play Store.
Though you may find similarly named apps on your system, in Aurora, in F-Droid, they may have different signatures resulting in failures to update sometimes.
Please note that Aurora Store will suggest you in the “Updates” tab to update some system apps (apps you didn’t install yourself, such as MicroG, Magic Earth or Pdf Viewer Plus). Long press on these apps and click on “Add to blacklist” in order not to update them with Aurora Store. They will be updated with /e/OS updates.
Note: This has been covered many times in these forums. Whenever you have an issue, search the forums. You might find the answers you need quicker than waiting for a reply.