I used ES File Explorer
Last time I attempted this I had xposed framework installed, since then I removed it, this time I used es file explorer for permissions etc.. and this time after reboot in system/app folder the app successfully installed after I prompted it to, I then came across that 803 error (or whatever it is) when launching remote play, so I went into supersu and uninstalled within the app, then the 803 error didn't come up.
Now I'm assuming after each reboot I'd need to go back to system/app and install remoteplay.apk for it to work, I read somewhere there is a workaround so you don't have to do this.
Now I just need to test when I get home which I'm sure involves more steps.
When you say create a secondary account on ps4, do you just mean I can use another account on my ps4
I have my main UK one but I also have American ps account and Indonesian account, can I just sign in with one of them? Then switch back to my main one after remote play has connected? or is it best to set up another basic uk one