Honestly hard to guess. These first two episodes covered 4 chapters, however it's worth noting that there are around 190 pages in those 2 chapters. It's supposed to be a two cour 24 episode anime, so my estimate is around 70 chapters, tho they could go for more with good pacing in the matches.
Not sure what to tell you lol. The manga is great, however when it comes to sports stuff I prefer to watch it. I started this way before the anime, so I went with the manga. I understand your gripe completely lol. You can probably binge the entire manga by the time episode 5 is out lol.