[S1, S2, S3 Volumes)(https://drive.google.com/drive/u/0/mobile/folders/16aIw10AFJIweUYtPpe0Vi6clXcEssnYR) - Only half the stuff was adapted, there's more in the novels. Shin won't make some sense without the previous LN's.

There are two manga adaptations.

Oregairu Monologue Manga - This follows the events anime adapted but with how they actually happened in the LN and doesn't change the story. You can find this manga easily by searching for it.

Oregairu Comic - This follows the LN events and has arcs not present in anime and it is also the same as the LN. This manga is hard to find so here - Oregairu Comic

Note : Both manga have reached up till the start/half of s3 events only but there's tons of new stuff before that so it shouldn't matter much.