Google authenticator iOS app crash / fails to load after iOS 14.2 update
You have to reinstall the application without deleting it:

Go to Settings &gt; iPhone Storage
Find Authenticator
Tap &quot;Offload App&quot;
After the process tap &quot;Re-install App&quot;

This provides to remove and install the application part, not your data/tokens. Your data remains.
I tried and succeeded on iPhone XS iOS 14.2.