Hi!
Like I said, a matter of taste. I Do like the songs of "Beyond the misterious Beyond", "Family", "No one has to be alone" (one of my absolute favorites) and "Bestest friends" very much, all of which are from the movies whose music you don't like. I also found all of the LBT 6 songs, "Very important creature" from LBT 7, "Imaginary friend" from LBT 9 and "Adventuring" from LBT 10 quite alright. The number of songs I really dislike is much lower. it would be "Good Inside", "The lesson", and "Me and my Dad".
It seems you like LBT 9, 10, and 11 better than 6, 7, and 8. If so, what is it that makes you give up hope and taking it for granted that the quality of future LBT movies will decrease?
I try to be a realist, but being no whatsoever kind of "prophet", I am not able to tell what will happen for sure. And so long there is the choice between dreading the worst and hoping for the best, I'll always go for the later.