The solution to this issue was presented in the thread: https://powerusers.microsoft.com/t5/Building-Power-Apps/PowerApp-Requires-Premium-Incorrectly/td-p/622088, thank you @homol and @v-xida-msft.
I followed the idea of the thread, but the details were different. In my case, with all Premium connectors removed, I exported my app with the "Create as new" option. Then I deleted the original app. My hope was to re-import as new and the issue would be resolved. This did not work. Further, I will now need a new link for the app users.
What did solve the issue was unpacking the zip file. Here are the files I saw:
I drilled down the folder with a long sting of numbers: \Microsoft.PowerApps\apps\10...
From there, I applied the solution from the other thread I referenced. In the JSON file, find "databaseReferences" and remove the previous code:
"databaseReferences": {
"default.cds": {
"databaseDetails": {
"referenceType": "Environmental",
"environmentName": "default.cds"
},
Replace with "databaseReferences": {}
I re-created the zip, re-imported and the app was restored as Standard.
