Cortech makes nice bags. I got my tank bag from Hitchcock's Motorcycles in the UK. They specialize in Royal Enfield motorcycles, and they carry all sorts of parts and accessories for them. They carry RE parts going back to 1939! The tank bag I got, though it has no name on it, is a nice bag. It has two magnetic flaps that velcro together when not in use. It has a mesh pocket in the top. It has a map pocket on the top. It has a carrying handle. And, it's expandable. I ordered mine from Hitchcock's mainly because they carry parts that are tailor made for RE bikes, including the Meteor that you and I have... :)
In that rear pocket with the hole thingy, you could put an powerbank into that and lead the Cable out the hole. If you have the phone out to navigate but you dont have another way to charge for example.
Love Cortech Tank Bags! Thank you needing one for my wife's 350! I used on for years on my Bonneville and it never scratched the tank. Took off to go into work most days.
You maybe able to use the small compartment next to the handle strap to hold a battery power bank. You can run the wire from the bank through the small hole and connect it to your phone, radio or camera.✌🏽
