You don't want to compare these two. Laravel is a high-end complete PHP framework including a tons of out of box features, while bootstrap can be used in a eg: Laravel project. Bootstrap is a CSS framework that you can use in almost any web project. React, Vue, Angular, jQuery, PHP, Python, Ruby etc...
To answer your question, if I must choose, I stick with bootstrap, because I can use it in a react project that is powered by a node express backend. I don't prefer PHP nowadays.