Есть строка:
"asassak jsnksknm4m kfklmdf <sfd5llkjkj> jsdjsdihgbwjbfbw"
Первые два пункта решил:
/<([^а-яё>]){6,}>/i
"asassak jsnksknm4m kfklmdf <sfd5llkjkj> jsdjsdihgbwjbfbw"
/<([^а-яё>]){6,}>/i
<((?=[0-9])[^а-яё>]{6,}|[^а-яё>]{1,}(?=[0-9])[^а-яё>]{5,}|[^а-яё>]{2,}(?=[0-9])[^а-яё>]{4,}|[^а-яё>]{3,}(?=[0-9])[^а-яё>]{3,}|[^а-яё>]{4,}(?=[0-9])[^а-яё>]{2,}|[^а-яё>]{5,}(?=[0-9])[^а-яё>]{1,}|)>
pcre.ru/eval/%3C((%3F%3D%5B0-9%5D)%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B6%2C%7D%7C%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B1%2C%7D(%3F%3D%5B0-9%5D)%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B5%2C%7D%7C%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B2%2C%7D(%3F%3D%5B0-9%5D)%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B4%2C%7D%7C%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B3%2C%7D(%3F%3D%5B0-9%5D)%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B3%2C%7D%7C%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B4%2C%7D(%3F%3D%5B0-9%5D)%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B2%2C%7D%7C%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B5%2C%7D(%3F%3D%5B0-9%5D)%5B%5E%D0%B0-%D1%8F%D1%91%3E%5D%7B1%2C%7D%7C)%3E%40%3D%23%3D%40101%40%3D%23%3D%40asassak%20jsnksknm4m%20kfklmdf%20%3Caaaaa6%3E%20%20jsdjsdihgbwjbfbw/