Is the novel good? Bc both the anime and Manga are not imo

I've only read 2 volumes then dropped it.
imo Book 1 was great and really original. The premise is good despite the awkward pacing BUT from there on it just goes down.

I heard from others that don't love a serie just because it's "loser becomes OP with a harem" say the same too: Great start, slow pacing but writing gradually turns bad both in terms of events (plot holes, inconsistency, bad fighting scenes and pacing) and characters dev.
I remember the majority of people who read the books said so after asked if the pacing improved in book 3.