An entry in Fortnightly Topic Challenge #42: Wordless Connecting Walls
Today, I received a rather peculiar mail from L.B.G. (Low-Budget Gladys), Glady's cousin, thrice removed (and aunt to the daughter of knock-off Gladys)...
Heya, North! So, a couple of weeks back, I went to go watch a WONDERFUL virtual concert- oh! it was just fantastic! Granted, some of the locations [needs improvement], but it was generally amazing because I could go anywhere without leaving my couch! Leave it to my some distant cousin to actually go to places. Always [spam[sic]] me with those puzzles. But instead of being [rude and abusive] to my cousin, I figured, I'll just [duplicate] what she does!
Lovingly Yours, L.B.G.
I have... no clue what she's talking about, but can you help me figure out where she went?
Overdue hint #1 updated:
One of the categories has to do with dogs. Think herding dogs.
Hint #2 (slightly updated):
One of the categories has to do very specifically with the flag itself.
Hint #3:
The Wikipedia page for Switzerland isn't loading properly for some reason. It's in the same category as Brazil and China. And Turkey.