Is gathering after the janaza a bid’ah?

Asalaamu Alaykum, I wanted to ask, a lot of people in my culture do something called a “Khatam” after the janaza, where all the men will gather in the mosque for 3 days and the women in a house, and they’ll sit for these 3 days reading Qur’an and they’ll serve food to everyone in the gathering. They’ll even have the seeds of eaten dates where they’ll be reciting something on each of them and placing them in to a bowl. Also they’ll ask people in the gathering to read a certain Surah or chapter from the Qur’an, a certain amount of times and to inform them once they’ve done so. So I wanted to ask if there’s anything in the Sunnah about this, because to me this seems like an innovation and something made up.