Rename them. TB sorts the server accounts in alphabetical order.

Open Account Settings and arrange the order of accounts in the left pane by drag and drop.

The Thunderbird I am using 128.6.0 does not sort alphabetically.

I have opened Account Setting and manually rearranged my email account. When I leave Account Setting, my email accounts are still in the original order. I have tried this at least 8 times. I have rearranged them, then signed out and back in and they are still in the original order.

Please follow sfhows' suggestion. In account settings, highlight an account and, while left mouse is pressed, drag up or down in the list.

I have tried that many, many times. I can rearrange them while in Account Settings, but when I go to open my email, they are all in the original order.

Try this: Help/Troubleshooting Info, Profile Folder, Open Folder, close TB, delete or rename folderTree.json, restart TB, and see if the accounts in the Folder Pane are ordered as they are in Account Settings. If not, see if the order can be applied in troubleshoot mode (hold Shift when launching TB).