By traveling here Aliens have demonstrated the ability to actually manufacture technology more advanced than ours. Even their method of transportation would be an existential threat.

Inventing the concept of new weapons isn’t the same as building them at a scale capable of wiping us out. Cobbling together a human vaporizing ray out of toaster parts is pure fiction. You might as well worry about AI developing the ability to perform magic spells.

In reality any new weaponry takes time, space, and effort to build. The idea of an AI building secret factory in the jungle producing indestructible flying death cubes is the tech bro version of preppers who the woke up every morning worrying that Obama was going to take over and enact sharia law.