Anyone can build their witness node as long as you can manage your own server or someone to manage for you. Can afford losing some $$$ money in the process. Though if you have a lot supporters e.g. Whales and friends, ask them to vote for you.
And extra hours hanging out :)
And guess what. I've created a step-by-step procedure on how to Setup a Witness Server too.
https://yehey.org/witness-update/@yehey/howto-setup-witness-node-by-yehey-updated-tutorial-guide
We love to see your Witness node up and running.