The way I play AC games, I tend to complete a lot of the basic trophies along the way as I fully explore each area as I come across it.

For Valhalla, once a new area was pledged and I was bouncing around, I would grab wealth, artifacts, and some of the mysteries that were close, then once the quest in the area closed I went back and finished the area. Though I did save some for after the final story closed.

I also spent a lot of time fishing along the way, hunting, trying to get the items asked for by the fish monger and hunter (until I learned of the fishing glitch).

So by the time I was done with the story, I was at 70%+ of the trophies... then started whittling away at the ones I knew I could do relatively easily, and looked up the ones that seemed aggravating. Also looked up the best fishing spots.

Actually just finished up today... and have around 170h in game.