Did you miss the one punch man wielding an axe? Or the guy dressed like batman with wrist cuffs like spiderman and a pair of shorts like heman? Honestly all the easter eggs were great!
If you finished all the way up to S.3 then I'd say start reading at chapter 190. It's right at the end of S.3 into the beginning of the 1st cour of S.4. If you want to read from the ending of S.4 then start around 248. But you'll miss some chapters on Nekoma and Fukurodani if you do!
The bL IS COMING! IM WITH YOU ALL! FINALLY IF THey could STAY LIKE THIS! And shion would stay a man for life.