My own Nexus 5X, also purchased when they were the hot new thing, has been doing better than yours. It does occasionally get janky, and a reboot will generally fix it. I do that maybe once a week and it's fine.

I just purchased another Nexus 5X to be my daughter's Very First Real Phone. (Using Google Fi to get it on the cheap, and it's unlocked so easy to switch later.) We'll see how that works...