The Eid salah is the reverse of Jumu'ah in that it's the salah then Khutbah not Khutbah then salah. I read you must stay until the end of the Khutbah but is there a valid view to leave after the salah as I see some brothers do either ignorantly or via a valid view of the scholars?
It is permitted to leave during a sermon unless it is a sermon of jumu'ah. This is due to the fact that the juma'h prayer is fard 'ayn (obligatory on every male Muslim unless he has a valid excuse, note that the majority considers the khutba as a necessary condition that's why leaving during the khutba therefore needs strong and valid excuses like saving a soul (see for example -in Arabic- islamqa #216139, a major reason for the necessity to witness it is that during the time of the Khutbah trade is not allowed (62:9)), while other sermons as such of the Eid prayer and that of salatul Isitisqaa' (asking for rain) and the Eid prayer are sunnah mu'akadah (optional but highly recommended).
It even has a basis in the sunnah:
I attended the 'Id prayer along with the Messenger of Allah (ﷺ). When he finished the prayer, he said: We shall deliver the sermon; he who likes to sit for listening to it may sit and he who likes to go away may go away. (Sunan abi Daowd)
It was also narrated that the Emir of Medina Marwan during the time of sahaba delivered the sermon before the prayer as the people used to leave after the prayer, but the sahaba rejected this doing:
The Prophet (ﷺ) used to proceed to the Musalla on the days of Id-ul-Fitr and Id-ul-Adha; the first thing to begin with was the prayer and after that he would stand in front of the people and the people would keep sitting in their rows. Then he would preach to them, advise them and give them orders, (i.e. Khutba). And after that if he wished to send an army for an expedition, he would do so; or if he wanted to give and order, he would do so, and then depart. The people followed this tradition till I went out with Marwan, the Governor of Medina, for the prayer of Id-ul-Adha or Id-ul-Fitr. When we reached the Musalla, there was a pulpit made by Kathir bin As-Salt. Marwan wanted to get up on that pulpit before the prayer. I got hold of his clothes but he pulled them and ascended the pulpit and delivered the Khutba before the prayer. I said to him, "By Allah, you have changed (the Prophet's tradition)." He replied, "O Abu Sa`id! Gone is that which you know." I said, "By Allah! What I know is better than what I do not know." Marwan said, "People do not sit to listen to our Khutba after the prayer, so I delivered the Khutba before the prayer." (Sahih al-Bukhari)
Therefore there's no harm in leaving the mosque or musalla after having prayed the two raka'a's of the Eid prayer.
My major source -in Arabic- islamweb #29911.