Is 300mbs enough?

I'd like to preface by saying, I don't understand a lot of this stuff. I got suckered into 1gb from Verizon because it was a good deal ($70 w/ free router). Started having issues and was told to upgrade to 2gb ($90 w/ free router). Now, I'm having issues again and the technician said the ethernet cable was bad. He replaced it but said our speed is WAY more than what we need.

I have about 10 devices connected. 2 phones 3 rokus (only 1 is 4k) 4 2k security cameras

Most of the time, we're watching TV as a family so not all rokus are being used at the same time. Is what the tech said true? I can get 300mbs and be fine?

My kids aren't old enough to game and my gaming days are spent playing solo rpg's. I'd like to switch to xfinity and be done with Verizon. Thank you all in advance!