Hi,
Which version of Avast and Thunderbird do you have installed?
Does it help when you temporarily disable Web Shield in Avast?
Avast : 22.6.6022 (version 22.6.7355.731)
Thunderbird : 102.0.2 (64 bits)
Windows 10 21H2
I succeed upgrading Thunderbird by deactivating Avast for 10mn.