I wasn't going to get into this but if you just got new frets and they are buzzing, the odds are overwhelming that something is wrong on the fingerboard end, not the neck/body joint. Or to put it another way, if it didn't do it before the new frets, it still houldn't do it now.

Forget the shim, it's a bad idea that is the wrong solution to the problem that hasn't been diagnosed yet.

No one is saying the frets are uneven.

When a guitar is refretted. Often the crowning proccess will leave the frets feeling rough. Nothing wrong with that, a bit of playing sorts it out. All I'm asking is, are you mistaking rough feeling frets with string buzz.

If it's not happening amplified then it's most probably your technique thats causing the problem. You're being too heavy handed with the strumming hand the most likely culprit.

Or just try raising the action/lowering the pickups.

The new frets feel smooth actually. I could hear it picking lightly near the bridge but if i pick near the neck, the notes are clear. I laid a straight edge on top of the 12th up to the last fret. I can see a wee bit distance somewhere around the 14th. It's telling me the last fret is taller than the preceding frets down to the 12th.