ISSUE: When unity exports or builds AAB or APK, Google Play Console will not accept the package because the game package is not made with ARM64 architecture.
RESOLUTION: Change Scripting Back-end to IL2CPP
Go to: Edit > Project Settings > Player > Other Settings (its a fold out blade) > Configuration (section of blade).
Change MONO to IL2CPP.
This will make ARM64 available.
REF:
When I tried searching for a solution to this problem, I did not see it initially. So I figured I would post the solution I found here.