After numerous attempts and various suggestions, I finally stumbled onto a remedy for this issue. Refer to the February 14, 2022 answer from Sümeyye Çakır in the following post:

"The credentials supplied to the package were not recognized" error when authenticating as server with certificate generated using BouncyCastle

In my case, changing the "Load User Profile" option from false to true on the affected application pool did the trick.