Big Sur mail won't send email

Just found, In absence of my ability to access / use email (iCloud & Yahoo) via my Apple mail, I searched and opened both accounts individually on Safari and now have ability to access and respond to those accounts separately. Following Big Sur update, after all this non sense, I may just delete my iCloud mail accounts for both Yahoo and Apple and continue working separately in this manner. This also has its advantages over relying on multi function via iCloud.

Big Sur update freezes email with every attempt to send or input a contact name. Apples spinning beach ball of doom freezes sytstem.