So I was able to add a delay when using abilities, to prevent swapping mid abilities. I have not been able to successfully block swapping after swapping without issues.
To block swapping during abilities in the QuickbarSlots Ability, add a check after the Wait Gameplay Events. You just need to get the ASC of the owner, check if it has a Tag that is added during ability activations. To do this you Make Gameplay Tag Container using your Block Tag. Then use Has Any Matching Gameplay Tags with a Branch node. Then in every ability you want to block weapon swapping you just add this Tag in the Ability Activation Tags.
I tried creating a GE for a cooldown using this Tag and adding it after the Swaps and Index selection, but I had a weird delay that kept incrementing. If you figure out how to do the latter part I’d love to know. Good luck!