I've a brand new good quality Epiphone semi acoustic gibson copy I bought cheap 3 or 4 years ago,
I tweaked bridge and trust rod as best as I could for my preferred lowest string height.
But still had a little fret buzz.

So I raised the string gauge to a new set of Ernie Ball Power Slinky 11-48 - problems solved...

[can't remember if the guitar was factory fitted with 9s or 10s...???]