@Rexfan1333 You mentioned the MCU, and I actually had an idea to write a fanfic about Ben 10 in the MCU. The Omnitrix would have one of the infinity stones (just like Loki's Scepter had one) and Gwen would be an Inhuman (if you watch Agents of SHIELD, which is also set in the MCU, you will understand what I'm talking about). I thought about starting from Age of Ultron, replacing Quicksilver and Scarlet Witch with Ben and Gwen. But ultimately I decided to write Watch Boy & Lucky Girl because mixing MCU characters would require more skill and talent than I have at the moment.
But as I said, I'm talking about real possibilities, and unfortunately, I don't think Ben 10 with Marvel is a realistic possibility.
And of course, in my comic book reboot idea Ben and Gwen wouldn't be kids, they would be at least teenagers.