Is there any way to unsubscribe to every add-on I have subbed on the workshop?
Not technically unsubscribe,but you can delete your addons file
You can use -noworkshop to disable workshop subscriptions ( You can then remove the command line option/parameter to get them all back )
If you must actually unsub, what you can do is shove them all into a collection and press unsubscribe on that collection.
you can disable all addons in the addons menu