Question Any chance to get the Key (or the SignOn Certificate?) that's used to sign my App?

[Migen]

Greetings AppYet,
My App "com.supersporti" was 1st build in AppYet platform, but was removed 4 years ago from PlayStore because I had not updated the Privacy Policy.
Last month I decided reinstate the App in PlayStore and updated it with a fresh APK from AppYet platform, but since all the content of the App is in Webview module, NO adds are showing.

From that moment, I decided to freshly rebuild the app by myself using Android Studio by working on top of a Premium App Template.

Now that I finished rebuilding the app from Android Studio, I`m trying to upload my own APK in PlayStore but I get the message:

You uploaded an APK that is signed with a different certificate to your previous APKs. You must use the same certificate. Your existing APKs are signed with the certificate(s) with fingerprint(s):

SHA1: 76:6D:3F:4F:48:76:B5:08:94:A4:EF:56:FB:37:5C:18:8C:15F:96

and the certificate(s) used to sign the APK you uploaded have fingerprint(s):

SHA1: E1:33:93:58:BF:6A:21:38:76:82:00:ED:94:21:EB:F4:B9:BF:4A:B8

Whilst, if I try to Opt in to Play App Signing with my own keys, I get the message:

The private key does not match the certificate we know for this app.

I contacted Google over this issue and they told me:

I understand you're not able to use the original keystore for your app, com.supersporti.

Unless you are enrolled in Play App Signing, the only solution to this issue is to publish a new app with a new package name and a new key. In order to transition existing users to the new app, you’ll need to update the original app’s description with a link to the new app and unpublish the original app.

Being unpublished and un-updated for over 4 years, there`s hardly any active devices with the App installed currently, but I`d like to keep hold of the downloads number and the rating reviews averaging 4.3, therefore before following Google's advice, I`m wondering...
Is it possible to get a copy of the Key and/or the SignOn Certificate used to sign "com.supersporti" in AppYet, or whatever might help me sign the APK from AndroidStudio and produce the same Certificate/Fingerprints whilst uploading a release in PlayStore ?