The anime covers very well the content of the LN so you don't really need to go back to read these volumes, but each volume is 'big' as the author complains every time in his afterword. The world-building is cut short in the anime which is fine for me but you might wanna check that out if you're a big fan or have some time to read from the beginning. In my opinion, though the world-building and the extra explanations are great, I find myself distracted in these parts a lot. I've read the LN till volume 10, with the season 2 part 1 ending atthe 5th volume I can say that the 6th volume is good as f.
I read the WN version of the story years back and there are some changes with how a few characters are portrayed and how the situations and circumstances change a bit, overall I felt the LN more refined and up to my taste.

Volume 8 and 9 were more slice-of-life oriented which was a bit of shame and was about to drop to the novel for the time being, but the last bonus chapter of Vol 9 sparked my interest again, and volume 10 was fantastic in my opinion and ended at a high note, here hoping for quicker translations cause the covers for all the upcoming novels are dope as f.