I went back, scoured my passwords, changed/updated 365 and that did not work. This has been a four hour process and I DID change my login password - I forgot - so for anyone else that faces this it IS your MAC login password.
However, I noticed that the Microsoft 365 I bought several years ago for a Windows laptop through Best Buy, and had expired but they still wanted payment to renew the subscription, was giving me the WRONG installer. I had to go back to Best Buy and cancel that subscription before I could install the new 365 for MAC that was bought with this computer. I now have Word, which is all I care about. Thanks for your response!