If OneDrive is enabled it can be that ESO is not liking that and your addons addon manager is empty ingame as it does not detect ANY addon installed :-(
I guess you need a seeing friend to validate that for you.
You'd have to disable OneDrive's "save my documents" to make ESO detect it properly again.
You can also take a screenshot ingame and look at the top right corner what folder is shown there, but as you cannot see it that's no way to detect the correct addons folder for you
AddOnSettings.txt
If the file is not updated it's either blocked by your Antivirus (Microsoft Defender e.g.) and you need to whitelist/allow it and eso64.exe to have access to the users/Elder Scrolls Online folder + subfolders.
If addons are found in your live/AddOns folder:
The file needs entries like this for example
Code:
#Default
<addonFolder name> 1
Where <addonFolder name> must be the exact name of the folder in live/AddOns, for example "FCOAccesibility" or "LibAddonMenu-2.0"
The #Default entry should work for ALL of your toons/characters then.
Here is an example file with the header version, the addons enabled, and 2 example addons (2 addons, 2 libraries) enabled for all toons/characters
Code:
#Version 101038
#AcknowledgedOutOfDateAddonsVersion 101038
#AddOnsEnabled 1
#Default
AddonSelector 1
FCOAccesibility 1
LibAddonMenu-2.0 1
LibDialog 1
You can copy that and add the other addon names below.
But with these addons enabled (AddonSelector, LibDialog, LibAddonMenu) it should at least help you to open the Addon's manager via the chat command /addons