Anime vs Manga Timeline Confusion

So I've watched the anime and I've read the manga, I'm debating starting the Web Novel.

Does anyone else also struggle with going back and forth and how the timelines of events is being mixed and matched? I just went back to the manga and read 104-107 today and was like... why are we re-visiting the "Show your new technique" tournament thing... and I've been trying to find the same tournament in previous chapters and couldn't lol. I must be remembering seeing these events in the anime? This whole time I've been like why are we getting these useless chapters that cover the same story we've already been told? LOL