I find it useful to impose a restriction on what social media I access on my phone. Basically, if I can access it from the Chromebook I use it there. When I can't, I switch to the phone. Mostly this is because I hate virtual keyboards. However, doing so has been helpful for me in dividing phone-like communication from journal-like ones. I recognize this is arbitrary and personal but it works for me.
Also, the phone camera is no match for my actual camera.