I run a robotics program for a local nonprofit, we have a couple FIRST Tech Challenge teams and a FIRST Robotics Challenge team.
Whenever we talk to other people about it the first thing is always, "is this like battle bots?"
(Sadly no, the bots do compete in tasks, and the level of completely is actually much greater)
Once you've built a few robots you'll learn its really not that hard, these dont have incredible complexity or intricacy since they are completely teleoperated (not autonomous) or do really complex things.
They just have to be tough as shit and design in a way that repairing is easy. Just like racing and everything else, having sponsorship is key bc you're gonna burn through a lot of materials....
BattleBots has evolved considerably over the years.
Fyi theres a thing called "sumo bots" where you build a small robot that pushes another robot out of a circle ring... on its own.
You can build a basic one for about $50, a more reasonable for around $200, and a comp bot about $1000. Its a really awesome, easy community STEM activity.