5 overseas players seems tough atm but i see this is happening in the near future if they are planning to expand the IPL teams to 12.
What we have seen during the IPL 2020 is that the limitation of 4 overseas players in the playing XI has meant that a lot of promising players were unable to find a slot, while among the local players there were a number of undeserving ones who managed to get included (to name a few, Kedar Jadhav of CSK, Sarfaraz Khan of KXIP, Shahbaz Nadeem of SRH.etc). Increasing the limit to 5 would mean that only quality players are included in the XI.
https://cricnerds.com/ipl-2021/ipl-2021-released-players-list/