Clarification on Requirements for Uploading Private Apps to a Managed iFrame (Developer Account & Payment Needed?)

Question

I'm need to upload a private app to a managed google play iFrame for internal use within our organization. I’ve reviewed the available documentaion thoroughly, but I still have a few questions and would greatly appreciate any insights from those who have experience with this process.

Is a Google Developer Account required to upload private apps to a managed iFrame? I understand that Google Play Console accounts are typically required for public app distribution, but I’m unsure if the same applies in this case, given that this is a private app only intended for a managed environment.

Is there a payment required for this setup? I’m aware that there is often a fee associated with Google Play Developer Accounts, especially for app publishing, but I’d like to confirm whether this fee also applies to private apps used solely in managed iFrames.

If anyone who has gone through this process could provide guidance, it would be incredibly helpful. Thank you very much in advance for your time and assistance!