Попробуй
classList.toggle(".class")
let blocks = document.querySelector('.blocks');
let block = document.querySelectorAll('.block');
let bigBlock = document.querySelector('.big-block');
let blackbigBlock = document.querySelector('.blackbig-block');
blocks.addEventListener('click', e => {
if (!e.target.classList.contains('block')) {
return;
}
[...block].forEach(el => {
el.classList.toggle('active');
});
//e.target.classList.add('active');
blackbigBlock.classList.toggle('active');
bigBlock.classList.toggle('active');
});