I have a history with these devices!!
Firstly I had an Rii mini i8 but, like you, I found it impossible to use

. I confined it to a cupboard.
So I bought an Rii i6 which was not much better! I soon abandoned that one also.
Then I bought an Rii MX3, but the corners dig into you palm so it's painful to use

!. Another one abandoned.
I now have an Rii mini i25 airmouse. It's not 100% perfect but it's the best so far. It has rounded corners

.
I agree with Mount81. Apps on phones or tablets are not the best way to control any media box!