Is an iPad 2? If so, it’s from March 2011 Not old by our standards, but old by tech standards.
I still have an iPad 2, and even the original iPad 1. Both can be used for Plex and Netflix, and a bit of youtube.
No real security issues with it, as long as it stays inside your house. I wouldn’t use it to do banking while on public wifi, for example. But don’t sweat it inside your house.
BTW, we have 2-year old Android devices that don’t receive updates. Heck, my Android phone was brand new and didn’t receive any updates for a year. I finally installed Lineage OS on it, because it was clear that the carrier was never going to update it.